Aces High Bulletin Board
General Forums => The O' Club => Topic started by: Heater on June 01, 2009, 07:07:22 AM
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01 June 2009
Brazil's Air Force says it searching for a missing Air France passenger jet near the the Brazilian island of Fernando do Noronha.
An Air Force spokesman says the search and rescue mission began Monday morning after the jet failed to make regular radio contact.
The Airbus A-330, carrying more than 216 passengers and 12 crew members, was traveling from Rio de Janeiro to Paris.
The plane is long overdue for its scheduled (0915 UTC) landing at Charles de Gaulle airport.
http://www.reuters.com/article/marketsNews/idUSN0133338520090601
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Apparently it was lost WAY off of Brazil's coastline. In fact it was lost far enough away that planes from Africa are involved in the air search as well. No one really knows where this plane was when it was lost.
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This is the 3rd "accident" regarding an airliner out of Brazil in recent times....
I wouldn't fly in or out of there.......
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This is the 3rd "accident" regarding an airliner out of Brazil in recent times....
I wouldn't fly in or out of there.......
Really? :confused: I did not know that
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Not a big fan of Airbus....
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This is the 3rd "accident" regarding an airliner out of Brazil in recent times....
I wouldn't fly in or out of there.......
There have been more. While I might not ride around on some low rent operator I wouldn't think twice about getting on Air France tomorrow. Nor would I feel bad about hopping on Delta going back down to Sao Paulo.
Not a big fan of Airbus....
That's pretty foolish. The A330 is, aw hell, no point even trying to have a conversation about it.
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That's pretty foolish. The A330 is, aw hell, no point even trying to have a conversation about it.
QFT
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Yup... the airbus did its part. It sent automated messages reporting electrical problems and cabin pressure drop. Seems it went into a storm. It would have to be unusually bad to bring down a big bird like that.
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It must have been something catastrophic that happened very quickly to have kept the crew from sending out a distress message. unless the "circuitry" failure had something to do with the A/C radio's.
IIRC the alert msgs that planes send to their respective HQ's work on a separate system than the regular radio equipment.
It's also pretty unusual for a commercial jetliner to experience problems at cruising attitude. If or When they find her it will probably take years if ever to know what happened
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This is the 3rd "accident" regarding an airliner out of Brazil in recent times....
I wouldn't fly in or out of there.......
Actually Brazilian pilots are awful good. A lot of weather and flying in bad conditions. I used to fly around down there on business a bit and was always impressed with them. The real question I have is the plane itself. I never understood how a pilot could "break" a functional airframe just by using the rudder (AA 587)...been leary of the airbus ever since. My guess is upset/unusual attitude followed by catastrophic failure of the airframe...
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It's looking like over 200 people have died , I would like to think that until the crash report is published everyone could keep their own feelings regarding airbus/Brazil to themselves.
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Humble, that happened due to constant pressure exerted onto the vertical stab by vicious rudder movement. You try holding up a piece of carbon fiber in 240 MPH winds.
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Humble, that happened due to constant pressure exerted onto the vertical stab by vicious rudder movement. You try holding up a piece of carbon fiber in 240 MPH winds.
However... The flight system was supposed to prevent that.
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The official NTSB report of October 26, 2004 states that the cause of the AA 587 crash was the overuse of the rudder to counter wake turbulence. The A300 had accidentally flown trough the wake of a 747 and the 1st officer was incorrectly using the rudder in an attempt to stabilize the plane.
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However... The flight system was supposed to prevent that.
The computers are not in control of external forces acting on the plane. In this case the wake turbulence of a B747.
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Humble, that happened due to constant pressure exerted onto the vertical stab by vicious rudder movement. You try holding up a piece of carbon fiber in 240 MPH winds.
The airplane was within the tolerances allowing full movement of all control surfaces. The scenario in which an experienced pilot "broke" an airframe via control input is alarming. The NTSB happened to side with airbus but the reality is that AA felt that the flight control system was the root cause not the pilot. The simple reality is that pilots should fly planes...not software. Further the combination of very brittle components and a fly by wire flight system is a recipe for disaster. I'm guessing that the airframe here just failed catastrophically under high g's.
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Very brittle components? Is the Airbus weaker than other jets?
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I'm also wondering where Humble gets his info. I've never heard composite materials being described as "brittle" before.
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However... The flight system was supposed to prevent that.
There were some fundamental problems with AA's training program regarding unusual attitude and upset recovery. They had fighter pilots teaching fighter pilot things which we now know don't work with transport passenger jets.
The A300 does not have the same logic and protections built into it as the A320 you're referring to whether or not you know it. All Airbus are not created equal. The 300 has a very sensitive rudder control system.
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Simply put yes. Composites are basically epoxy. While metal will bend composites will flex and then break. Brittle does not mean weak, simply that when pushed beyond design tolerance the structure will fail and not bend. Basically instead of "popped rivets" and a bent airframe you get catastrophic failure. The reality is that a lot of the current technology in the Airbus is both cutting edge...and unproven. This applies to both the airframe itself and the avionics. The possibility that we have a convergence where the limit of airframe engineering and complexity of fly by wire computer driven avionics meet in a place that is potentially threatening to the airframe itself is very real. In any airbus the computer is actually flying the plane. The avionics interpret the pilots input and can and do modify them based on what its sensors tell it. This is heart of AA's comments to the NTSB. The sad reality is we're going to have a lot more aviation accidents over the next decade. A combination of inexperienced/low time/poorely trained flight crews combined with "just enough" engineering and focus on cost saving unproven technology has made it inevitable.
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Brittle in the sense that the failure of ceramic is brittle compared to metal's.
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That's plain silly humble.
Btw why are you using a computer to post here , using a chinese abacus should be safer , it's a proved technology !
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There were some fundamental problems with AA's training program regarding unusual attitude and upset recovery. They had fighter pilots teaching fighter pilot things which we now know don't work with transport passenger jets.
The A300 does not have the same logic and protections built into it as the A320 you're referring to whether or not you know it. All Airbus are not created equal. The 300 has a very sensitive rudder control system.
thats not completely true IMO. Airbus refused to hand over significant amounts of data to the NTSB. As for the flight control systems on the 320 (or any other airbus) the truth is that no one but airbus and the system manufacturer actually know the reality. Here is a snippit from Quantus which has had significant issues with A330-300's and turbulence....
Secret data may give Qantas a QF72 clue
Ben Sandilands writes:
A secret partition (internal computer wall) on the US-made air data inertial reference unit (ADIRU) that Qantas blames for the in flight crisis that forced QF 72 to make an emergency landing at Learmonth on 7 October is about to be unlocked.
Its existence, only hinted at in the preliminary ATSB report into the accident, is causing consternation among airlines for whom there is now a question mark over the serviceability of equipment critical to the control of modern airliners. They simply don't know the full information held by the ADIRU.
Crikey has been shown part of a private Qantas presentation on the accident, which injured 60 of its passengers and 14 of its crew aboard the Airbus A330-300 involved.
It draws attention to frequent unusual movements in the tail of the jet and disclosed that all three ADIRU units had be sent back to the maker, Northrop-Grumman because of third level data that was partitioned from examination by operators or accident investigators and could only be read in the Northrop-Grumman workshops.
This deeper level of data is apparently prohibited to users to protect proprietary aspects of the design from being copied or interfered with.
However the issue that has now emerged for the carriers including Qantas is that this secrecy might prevent them becoming aware of any deeper layer faults that should be fixed before an airliner is allowed to continue in service.
The Australian, French and US incident investigation authorities, and Airbus and Qantas will all be present this week when Northrop-Grumman starts unlocking all of the data contained in the three units on the A330, the two that appeared to work properly, and the one that ran amok.
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Sad. Thoughts and prayers for family & friends. :pray
ROX
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That's plain silly humble.
Btw why are you using a computer to post here , using a chinese abacus should be safer , it's a proved technology !
I'm sorry but if a given computer had a predisposition for PS failure that would kill the user you would want to know about it. The reality is that we have a combination of material choice, design criteria and avionics going where no one has before. A very significant event (AA 587) went largely unnoticed. Please tell me the last time any control input on climbout during normal conditions caused catostophic airframe failure?
Further that the manufacture refused to provide data to the investigating authority.
It is very possible that the current generation of composites is simply not suitable for use in aviation airframes.
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Please tell me the last time any control input on climbout during normal conditions caused catostophic airframe failure?
Is flying through the wake of a B747 "normal" conditions?
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Is flying through the wake of a B747 "normal" conditions?
Yes
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Lol composite is definately weaker than metal. That's why US army issues cast iron armor to all the combatants..
No wait.. :rofl
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I'm sorry but if a given computer had a predisposition for PS failure that would kill the user you would want to know about it. The reality is that we have a combination of material choice, design criteria and avionics going where no one has before. A very significant event (AA 587) went largely unnoticed. Please tell me the last time any control input on climbout during normal conditions caused catostophic airframe failure?
Further that the manufacture refused to provide data to the investigating authority.
It is very possible that the current generation of composites is simply not suitable for use in aviation airframes.
You're speaking of too many point at time (btw I apologise for the missing smiley in my previous post I was trying to be witty not offensive :))
Computer + composite is not always bad think of the shuttle for example of modern combat aircraft, it work.
And on commercial planes too, your post is (and I apologise again) very similar to a Boeing biased post of the period when Boeing was not up to date on composites :)
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Brittle in the sense that the failure of ceramic is brittle compared to metal's.
Composite materials used on aircraft are not made from ceramics. Most are carbon fiber reinforced polymers, or in other words: Plastics.
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Lol composite is definately weaker than metal. That's why US army issues cast iron armor to all the combatants..
No wait.. :rofl
I'm sorry if a lack of common sense effects you. "brittle" is not a reflection of "strength" or hardness. Lets look at a diamond, very hard...but very brittle and easy to fracture if hit from the wrong angle as well. Lets return to the fundamental fact here. An experienced pilot flying in normal conditions caused catastrophic failure by control input at a speed in which the plane in question was certified for 100% travel of all control surfaces.
Now lets say that was a school bus and the driver took a turn off a freeway ramp at 25 mph (a speed rated safe for both the tire and ramp) and that caused a blow out that killed every one on the bus...what do you blame the driver or the tire? Add in the fact that the bus was equipped with "smart drive" a computer system that over rode the drivers control inputs at its discretion....
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You're speaking of too many point at time (btw I apologise for the missing smiley in my previous post I was trying to be witty not offensive :))
Computer + composite is not always bad think of the shuttle for example of modern combat aircraft, it work.
And on commercial planes too, your post is (and I apologise again) very similar to a Boeing biased post of the period when Boeing was not up to date on composites :)
Airbus isn't up to date on composites either IMO. Thats not an attack on airbus, simply a statement of fact.
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Humble, in your analogy the bus driver would have to violently steer left and right repeatedly. On most vehicles on the road today that would break something, or even flip the vehicle. Full rudder input to either side would not have damaged the tail of the A300. Oscillating the input left and right very quickly did.
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Composite materials used on aircraft are not made from ceramics. Most are carbon fiber reinforced polymers, or in other words: Plastics.
No kidding.Composites are basically epoxy. While metal will bend composites will flex and then break. Brittle does not mean weak, simply that when pushed beyond design tolerance the structure will fail and not bend.
the failure of ceramic is brittle compared to metal's.
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Airbus isn't up to date on composites either IMO. Thats not an attack on airbus, simply a statement of fact.
Which composites do they use, and what composites are "up to date"?
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While metal will bend composites will flex and then break.
You do know that they use carbon fiber composites to make fishing rods? It's one of the most flexible materials known to man.
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Failure mode?
And I'm not arguing either way. Only what Humble meant.
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Usually delamination.
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...Add in the fact that the bus was equipped with "smart drive" a computer system that over rode the drivers control inputs at its discretion....
Its already been mentioned, but I guess you missed it: the A300 that crashed in New York did not have fly-by-wire. Its an older (1970's) design, predating the A320 which was the first Airbus to use the technology.
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The question isnt fly by wire specifically its the combination of avionics and material choice. If you read the NTSB report you have 2 different "theories". Basically airbus in effect claiming "pilot error" and AA claiming that the design created issues itself. The design of the A300-600 generates 6 times the force for the same control input as the A300B2. My question is fundemental, the choice of a material prone to catostophic failure at a speed of 250 knts.
It's not an entirely accurate comparision but using AH lets look at a plane suffering catostophic failure "at speed" vs one where you could stomp on the rudder during autoclimb and break the plane. I can recall no other incident ever in the history of commercial flight in the jet age where a pilot has induced structural failure at moderate speed via control input. This is IMO clearly a design flaw...
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FYI....
American argues that Airbus knew that the A300-600 and A310 were prone to rudder overcontrolling from three or four prior incidents dating back to at least 1991 that were presented in NTSB testimony (AW&ST Nov. 25, 2002, p. 44).
Calculations showed that these rudder motions overloaded the fin beyond limit load in several cases, and beyond ultimate load (1.5 times limit load) in at least two instances--a point at which the fin might be expected to break off. One of those ultimate load violations was on American's Flight 903 in May 1997 and the other was on an Interflug A310 in 1991. Other cases include an Air France Flight 825 incident in December 1999 on an A310 where limit load was exceeded.
A key document, American says, is a June 19, 1997, Airbus internal memorandum stating that in Flight 903's "rear fuselage, fin and empennage the ultimate design loads may have been exceeded." This knowledge did not come to the NTSB or American until the document was revealed after the Flight 587 accident more than four years later.
"With Interflug, you could say it was a one-off," says Bruce Hicks, an American spokesman. "But with 903 you have to connect the dots, and Air France 825 clinched it."
American claims Airbus knew of overloads but did not inform operators or authorities in sufficiently specific language that would catch their attention, nor did the manufacturer convey data about the series of rudder overcontrol incidents on the A300-600 and A310.
An independent study requested as part of the NTSB Flight 587 investigation showed that at higher speeds, where pilots rarely use the pedals, the rudder of these two types is 3.2-10 times more sensitive (in terms of deflection per incremental force) than other transports, with a breakout force several times larger than the incremental force for full deflection (see graph, p. 45). An NTSB poll of Boeing, Douglas and Airbus histories showed that no other type had this history of fin overload.
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The A300's rudder is certified to handle only a full deflection; that is, to travel from neutral all the way right or left, but not to swing alternately from far right to far left. It wasn't until the rudder had done this three times, with load forces almost twice the fin's design capacity, that the vertical stabilizer finally gave way. It is the pilot's responsibility to know the design limits of his aircraft and never exceed them. No matter how sensitive the rudder controls (and Airbus should be, and was criticized for that), a series of full deflections right and left cannot be viewed as anything other than pilot error.
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So from what I am reading then the computer thought the rudder input was needed and moved the rudder as the pilot requested. So the computer system can allow movements exceeding structural design capacity?
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So from what I am reading then the computer thought the rudder input was needed and moved the rudder as the pilot requested. So the computer system can allow movements exceeding structural design capacity?
What computer?
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Fly by wire................ computer. Or did I miss something.......
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Fly by wire................ computer. Or did I miss something.......
You missed something.
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If by "the computer" you mean hydraulic actuation then via the pilots feet then yes.
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Also, let's remember - the A330 that went missing today is a design generation newer than the A300 that came down over NY. Not sure how many comparisons we can draw.
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The 300 series not FBW but the 330 is. My initial post was not meant to infer that it was. The underlying issue is still the same. At a speed of roughly 250 knts the pilot should not have been able to break the plane. The combination of material choice and aircraft design created a problem that should have been impossible in the circumstances. Fast forwarding to the current scenario my concern is the combination of design and the significant documented problems already inherent in the 330 might have "lined up the holes". In my mind the simple words "what is it doing now" are the scariest in the history of commercial aviation. The available service history of composite materials in airframes is limited and I think its shortcomings are going to become more and more apparent over time.
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At a speed of roughly 250 knts the pilot should not have been able to break the plane.
All non-computer-limited airliners are breakable by the pilot at 250 knots. It doesn't take much to over stress them.
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It was a shoe-bomb.
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All non-computer-limited airliners are breakable by the pilot at 250 knots. It doesn't take much to over stress them.
You sure about that speed?
Anyway, here is an airbus linkie and the narrator is a Boeing guy. Very good ;)
Sort of blows away any theory that the Airbus folks are not aware of abnormal cirkumstances.
http://www.youtube.com/watch?v=IKBABNL-DDM&feature=related
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You sure about that speed?
If we use a B737 as an example it has a load limit of +2.5G to -1.0G, and the pilots handbook states: "Avoid rapid and large alternating control inputs, especially in combination with large changes in pitch, roll, or yaw (e.g. large side slip angles) as they may result in structural failure at any speed, including below VA."
Airliners aren't fragile, but they are fully capable of destroying themselves trough overly aggressive maneuvering.
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2.5G and -1, that's....nothing! Thought they could do a little more than that.
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They can, but not for long and not without incurring damage, and eventual failure. What you feel during take-off and landing is at most 1.5G. 2.5G is actually a lot more than most virtual "pilots" think.
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Those are pretty standard limitations.
A Learjet 45 is +2.9/-1.0 flaps up. +2.0/0.0 flaps down (any amount)
Citation Excel +3.0/-1.2 flaps up. +2.0/0.0 flaps down.
They're not fighter airplanes and are plenty rugged provided you keep them within their limitations.
You simply cannot do some things in transport airplanes that you could in a fighter or aerobatic airplane. Part of American Airlines issue was they had fighter pilot teaching fighter pilot things to airline pilots flying airliners regarding upset/unusual attitude recovery in their "Advanced Aircraft Maneuvering Program" which was partly to blame for the accident of AA587.
587 and this Air France accident have nothing in common other than they were fown in airplanes designed by Airbus built probably two decades apart.
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About the a300 discussion:
MYTH: I CAN FULLY DEFLECT THE CONTROLS BELOW MANEUVERING SPEED! - x-plane.com (http://www.x-plane.com/myths.html)
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Thats not completely true. All companies share a commonality of thought (with in). Airbus has pioneered development in a lot of area's in response to real or percieved needs of its potential customers. The two area's of concern for me are the use of composites and the ever more complex avionics that increasingly take over pilot work load. If we look at the AA crash the bottom line (from my perspective) is still very simple, the overall design was substandard and inappropriate for the materials used. The plane had control authority significantly higher then the norm in combination with an unproven material. Please show me any incident ever (commercial aviation) where a pilot caused catastrophic failure via control surface input at moderate speed.
Obviously any comments on the current event is speculative. One stark fact is that in the event of failure of the FBW system due to electrical failure the plane is only controllable by trim input, differential thrust....and rudder. So a failure of the FBW would leave the plane in a situation where the only major control surface available for unusual attitude recovery is the rudder. BTW the rudder in later build A330's is smaller then in the one that crashed...
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Please show me any incident ever (commercial aviation) where a pilot caused catastrophic failure via control surface input at moderate speed.
AA587 is that accident. There was nothing gentle, subtle or smooth about the flying pilots use of rudder during the upset recovery.
If I took those same actions in many other airplanes significant damage could/would/should occur and a catastrophic failure is not out of the realm of possibility. The tail did not depart the airplane because of one misguided input or a proper use of the rudder. Incorrect rudder inputs to the opposite several times in sequence did. That rests squarely on the pilot and the misguidance of the AAAAMP training for trying to teach him to be aggressive on the rudder in unusual attitude/upset recovery situations.
Vertical stabs just aren't designed to do that.
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the use of composites
Most of the composites in an airliner are not even structural components. Especially during the development of composites early on, no manufacturers were willing to make a spar, for example, out of composites. The floor panels, interior bulkheads, non-structural access hatches, etc. were the first components to be made from composites. Its only now, after significant research, are structural components of the airframe being constructed of composites. And, in my opinion, when properly engineered for the application, composites are and will always be better than their alluminum, historical predecessors.
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Vertical stabs just aren't designed to do that.
Well if you design them out of 2 foot thick steel they would. It would never leave the ground tho.
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I think Humble just put a foot in his mouth and is now trying to gag it out.
AFAIK composites are used for the exact reason that they're stronger and more flexible than steel counterparts especially when compared to weight. The fishing rod was an excellent example - how many steel fishing rods have you seen? It flexes and carries several pounds of load despite being tenth of an inch thick in the head. A metal would deform and snap broken after a couple movements.
Ceramic components can be brittle yes, but only if they're designed to be primarily hard. Ceramic carpet laminated on eachothers is not brittle especially when combined to kevlar / carbon fibre. It's basically as far from brittle as current tech can make.
The only way a modern aeroplane composite can be brittle is if an error was made during the laminating process and the lamination itself will break.
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The fishing rod was an excellent example - how many steel fishing rods have you seen?
A metal would deform and snap broken after a couple movements.
Hmm, there's one down at my grandmothers house, unless she got rid of it. It was one of my grandfathers old rods. A bit heavy, but otherwise quite functional.
Metal doesn't have to deform and break after "a couple movements". Depends on its formulation and temper. An example of a hard, fairly brittle metal that can handle lots of movement without deforming and breaking is a spring.
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Ripley, what's the failure mode of those ceramic/kevlar/carbon carpets like, compared to metals?
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Ripley, what's the failure mode of those ceramic/kevlar/carbon carpets like, compared to metals?
Under what condition (temp,pressure...) and compared to what kind of metal ?
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That's what I was thinking too. Just asking to see if there's any characteristic trend, or if it's a crapshoot from all the variables.
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crapshoot of variables look to be a good definition !
I'm pretty incompetent in RDM (Résistance des Matériaux/Strength of materials) as it was far from my preferred course I just remember some huge headache :)
The only thing I can say is : it's can be as simple as saying metal vs composite.
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They can, but not for long and not without incurring damage, and eventual failure. What you feel during take-off and landing is at most 1.5G. 2.5G is actually a lot more than most virtual "pilots" think.
I know. Jostle around in them little ones every now and then.
I hate - G's, yeachh!
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Hmm, there's one down at my grandmothers house, unless she got rid of it. It was one of my grandfathers old rods. A bit heavy, but otherwise quite functional.
Metal doesn't have to deform and break after "a couple movements". Depends on its formulation and temper. An example of a hard, fairly brittle metal that can handle lots of movement without deforming and breaking is a spring.
True but when weight is taken into account I think the scale tips over to composites. If I recall right they said the A380 could not have been built without extensive use of composites due to weight limitations. The brittle nature / stress factures issue is not when speaking about metals in general but when speaking about aircraft grade aluminium compared to composites.
The biggest problem (I think) at the moment is that the laminating process is very demanding as it requires a certain temperature to be successful. If the temperature is wrong (too low) the laminate doesn't adhere and becomes brittle.
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Isn't there a single discussion with americans anywhere on the matter of the missing plane without airbus vs. boeing hoopla!? Come on, you all have been discussing this like hundred times over in the past years and it only ceased for a while when the 787 experienced a delay, after there had been so much whining about the tiniest problem with the A380. There's no such thing as a perfect plane nor a perfect company and you can debate about that all day but it's not going to change. Neither company would be in the business if their record would be piss poor.
Now, about the missing plane... I've read from the news that supposedly some passengers were able to send short text messages with their cellphones to their relatives. Nothing was heard from the pilots, but there was still time to send text messages?
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I belive the passengers were worried about the bad weather and sent txt messages before whatever final event that made the plane crash. The text messages are several minutes apart and prolly not sent while the plane was going down.
Also im THINKING that maybe the pilots may have been busy trying to fly the plane
Their voice comms prolly does not use the same system for transmitting as cellphone communication on the plane either. Maybe the system the pilots used was out but not the cellphone system.
Many reasons why txt's got through and not the pilots vox.
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Very sceptical about the text messaging scenairo, most airlines haven't approved the use of mobile phones in flight, and if they did send text's they'd have to be in range of land. When you go out of Radar range in that area you are effectively out of VHF range, so you have to rely on the HF, which is always somewhat "iffy". So It is reasonable to assume they were in the "aviating part" of the flight, and couldn't/didn't have the time to try to communicate.
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Cellphones over sat. not that uncommon but dont know about air france
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Are you refering to the common cell phones everyone carries around with them, or those phones in the seat backs, for 10 USD a minute? I stand to be corrected but I really dont think it will hold up. Anything is possible.
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A quick google revealed that air france allowed mobiles on their planes back in 08. Their system is sattellite based and allowes for text and voice comms but not data. Since then i bet alot of airlines have implemented them.
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Not mine :), but ok...
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And sattelite based link once elevated from the ground is not iffy.
Not too sure about ATC standards, but a sattellite linked aircraft (GPS) could absolutely (in theory) forwards it's gps points to anywhere. Baffles me a bit, that there still is the "old" flying over vast areas of water.
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The "iffy" bit I was refering to was the HF, and It is still is the primary communications for Flights in that part of the world, not from the aeroplanes point of view, but the ground stations.
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How much would the use of ceramics affect the acceleration on a treadmill? Personally, I don't think they can handle it.
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Please show me any incident ever (commercial aviation) where a pilot caused catastrophic failure via control surface input at moderate speed.
Please show me any incident ever (commercial aviation) where a pilot commanded alternating full deflections of the rudder multiple times.
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My opinion is just that, an opinion. No question that composite materials offer tremendous potential benifits. However lets look at a few fundemental realities that are true to the best of my knowledge (feel free to correct)....
1) Composites flex then break, metals flex, then bend and then break
2) We have thousands of documented cases of "warped" airframes and "popped rivets" with metal
3) Composite planes have a minimal operational history so wear issues do to fatique are less well known
4) Regardless of pilot error in 587 I am unaware of a single incident ever of pilot induced strutural failure similiar to that prior...EVER
Looking at how this applies to the current situation based on the limited facts we have...
The 1st warning AF recieved was that the AP had disengaged and switched to alternate law. This preceeds any electrical fault issues and indicates some type of signifcant upset and/or mechanical/structural failure. The alternative would apparently be a massive electrical failure that took the plane to "recovery" alternate law (no indication of what mode that I saw).
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Didn't see this already posted, but some wreakage found.
http://www.bloomberg.com/apps/news?pid=20601085&sid=aGqVhPoRLAtM&refer=europe (http://www.bloomberg.com/apps/news?pid=20601085&sid=aGqVhPoRLAtM&refer=europe)
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Steel comes in various densities and composition. Steel making is a chemical process believe it or not.
There are literaly thousands of types of steel. All have differing physical and chemical properties based on the customers needs and use.
Carbon Fiber I don't know enough about to comment on. How many differing types of carbon fiber are there?
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Isn't there a single discussion with americans anywhere on the matter of the missing plane without airbus vs. boeing hoopla!? Come on, you all have been discussing this like hundred times over in the past years and it only ceased for a while when the 787 experienced a delay, after there had been so much whining about the tiniest problem with the A380. There's no such thing as a perfect plane nor a perfect company and you can debate about that all day but it's not going to change. Neither company would be in the business if their record would be piss poor.
Now, about the missing plane... I've read from the news that supposedly some passengers were able to send short text messages with their cellphones to their relatives. Nothing was heard from the pilots, but there was still time to send text messages?
Fishu, those with ACTUAL Aviation experience (Golfer, WW, etc) are the victims of noodle envy. MrRipley makes sense too, the rest are just trying to be "an expert".
I've notice a couple of people posting for "shock value" and someone bit on the Airbus thing.
It's a shame a plane goes down and people have to find the time to act like love muffines "because they're cool".
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Please show me any incident ever (commercial aviation) where a pilot commanded alternating full deflections of the rudder multiple times.
This is the problem here, your attempting to argue that this is a singular event. In 50+ years of commercial jet aviation it hasn't happened ever before (that I'm aware of). Have you actually read the NTSB report or are you just mouthing off what "everyone" says...the guy didnt "stomp on the rudder". The problem is a relatively complex combination of questionable training, simulator programing and the airplane design itself.
Lets look at the simple truth here. This is the 1st accident ever on this flight route which has been active since 1947 even though its easily the toughest weather in the world (for weather issues like this). Obviously a lot of stuff had to have gone wrong...my question and comments here are simple. A plane designed to be cutting edge in all ways might not be "safer". This is no different then the Titanic, no ship is unsinkable and no plane is completely "safe"....
So when we have materials whose real purpose is cost savings not safety and avionics that attempt to protect the plane from the pilot and engineering done to a standard of "just enough" all marketed under the banner of "safest and best ever" the end result is inevitably bad. Pilots need skill, training and experience. Airplanes need to be over engineered and as simple as practically possible. Flying is inherently dangerous and always will be....
The surprise for me is that the alternate law/AP disconnect came 1st. That indicates a massive upset or failure preceding the electrical faults.
In effect leaving the pilots chasing the avionics and then having a situation where it appears that the avionics may have gone totally offline....leaving the pilots with minimal control availability at unusual attitude in IMC in major turbulence...end of story. I'd almost 100% bet a 767 would have had no similar issues here....
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Fishu, those with ACTUAL Aviation experience (Golfer, WW, etc) are the victims of noodle envy. MrRipley makes sense too, the rest are just trying to be "an expert".
I've notice a couple of people posting for "shock value" and someone bit on the Airbus thing.
It's a shame a plane goes down and people have to find the time to act like love muffines "because they're cool".
I'm not looking for shock value and my comments are relatively simple and straight forward. Every aspect of aviation has gone from safety and engineering to profit and "ease of use". The reality is that in order to gain market share Airbus had to create an alternative positioning. This is business not engineering per se...
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So when we have materials whose real purpose is cost savings not safety
Composite materials often times are much more expensive than conventional materials. Composites offer designers a couple of different advantages. First, composites can be engineered to perform exactly the way an engineer needs them to perform. Be it in compression, tension, torsion, you name it, you can engineer a component to exhibit the qualities you want. The higher the percentage of reinforcement, the more the composite behaves like the reinforcement. The higher the percentage of matrix, the more the composite behaves like the matrix. Second, composites are typically much lighter but possess the same or higher structural qualities of the metal components they replace. Third, composites offer the ability to make very complex aerodynamic shapes that metals cannot be easily formed into.
There is a tremendous amount of historical data on composites, and it comes from the most demanding aeronautical applications in the world--the military. Planes as old as the F-4 and F-111 used composites to achieve weight savings. Almost every military aircraft since then has made more and more extensive use of composites since. I remember looking at an F-18 crash, and there was carbon fiber everywhere--I had no idea it contained so much of the material--the structural part of the wing is almost entirely carbon. These aircraft are designed to the highest tolerances, the highest structural characteristics, and are subjected to more punishment than any other aircraft in the world. So, to say that the materials themselves are a poor substitute for metal is not true.
Engineering can be flawed, no doubt. But, that does not ultimately mean anything with respect to the materials themselves. If an engineer uses an aluminum structural component the wrong way, it will fail.
In my opinion, composites are the future, and will enable designers to wring every drop of performance out of aircraft in the future. It doesn't have anything to do with cheaper--it has to do with better.
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Steel comes in various densities and composition. Steel making is a chemical process believe it or not.
There are literaly thousands of types of steel. All have differing physical and chemical properties based on the customers needs and use.
Carbon Fiber I don't know enough about to comment on. How many differing types of carbon fiber are there?
It is not the fiber, per se. It is the resin used to bind the fiber that is important. The other factor being the density of the fiber per square foot versus resin content. Resins are like metals. They come in many configurations. Virtually all airplane resins are based off the epoxy family.
Resins, in all families, continue to cure as they age. Epoxies form more polymer molecule chains to the fiber than any other family. They crosslink to other fibers in a high content fiber blends. In other words, they get stronger as they age. Now, here is the rub. Depending on the resin mix, they could get brittle as they age. However, that would take a major mistake in production for that to happen.
Resins can flex. Resins can bend. How the fiber is laid and the configuration of the resin determine how much flex and the orientation of the flex, will be tolerated before structural failure occurs.
Composites are far more difficult to work with in a manufacturing environment and thus add substantially more cost to the airplane.
Composites have been used for a long time in non-load bearing structures in order to test how well they perform as they age. I do not know if the results have ever been made public. It would be interesting reading though.
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You see the same thing in formula 1 and all kinds of racing and fast sailing yatch too. Has nothing to do with cost during the design atleast. The saved weight will save money over time but not at the cost of strength. Only time i would want steel in my boat is if i went to places with lots of ice or to far away places were a welding machine is easyer to find for repairs than a boatyard that can do epoxy fixes.
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I recognize that both composite technology and fly by wire are "cutting edge" and have been pioneered in military applications for a significant period of time. I also know that even simple epoxy can be stronger then steel (JB weld for example) and offer tremendous design flexibility. My simple questions remain....
1) Is there anywhere ever in the 50+ years of jet age aviation a prior case of pilot induced structural failure at moderate speed? I'm not blaming it on the composite entirely since the underlying design was at fault. However we have here a tortional effect and my understanding is that a composite by its nature is more susceptable to "snapping" if torqued against the grain so to speak then a metal component that might be nore prone to "twist" (again feel free to correct me)...
2) In a sudden upset at cruise speeds are the components engineered for the stress of recovery or are the systems designed to eliminate the possibility before an incident?
It seems that more and more the design criteria is to eliminate the possibility of an issue then survivability in the issue. To me accepting the argument that a pilot can snap the tail in an attempt to recover from unusual attitude in a wake vortex is absurd. Using Golfers Lears, has one ever suffered a similar fate?
Since the event started with an AP disconnect/alternative law and not an electrical fault that would appear to indicate unusual attitude do to turbulence (unless the avionics went nuts like on the Quantus bird). If that is the case then the either the airframe failed or the avionics precluded or contributed to the pilots inability to correct the upset. My comment is based on the rarity of turbulence induced crashes at cruise ? {I cant recall any but again correct me}....
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Most crashes are pilot error. Most lead-ups for a crash are pilot error too.
And the naughtiest, high-G fighters and even aerobatics aircraft are not necessarily more made of riveted alloys.
Saying that, where one aircraft would pop rivets due to stress, the "carbon" one wouldn't.
Problems with our synthetic materials would rather be UV and such IMHO.
As for this accident occuring on that flight leg, I have my doubts. First airliner with a 3 digit number though....
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Not quite right there humble.
There are resin/fiber combinations which have better memory than currently used aircraft metals. Pound for pound, there are resin/fiber combinations which are stronger than metal as well.
Now, where you may not want to use composites are in areas which have a constant high load force applied, such as a wing spar. Due to the nature of resins continually curing, a structure under constant high stress loads could form a new memory over time. That is theory.
This is an area still under going testing. "Scaled Composites" is really pushing the limits of composite structure and design. So far, the results have been rather impressive.
Without knowing the exact breakdown in the resin used, it is difficult to make any types of assumption as to the strength or flexibility of the component.
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forgive me for my lack of knowledge with aeroplanes and flights,
But if an airliner suffered engine failure would it be able to glide gentley down like other planes?
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Thats really where my questions are, composites have been used with much success in extreme enviornments where those properties are in effect "over engineered" to provide exceptional performance...often at high cost. We're now seeing the use of this technology in a more consumer driven market place where cost/performance drives purchasing. No question that "smart cockpits" are designed for the lowest common denominator of pilot skill. Engineering is driven by "maximum" performance for each dollar spent. Airlines are under tremendous pressure to cut cost per passenger mile and all decisions are driven by that. No question that Airbus is pioneering the road ahead...
The thought that scares me is that the combination of factors might have reached the point where the plane in question was the victim of these trends. Given the sheer # of operational hours 1 in a million is an operational certainty not an unlucky event. We have a very experienced crew in a state of the art plane that has suffered a catostophic failure of an unexpected type. We expect planes to crash due to pilot error, or weather (normally landing/taking off) or wind shear or terrorist events or even design flaws (DC-10/L1011) in combination with mechanical errors. I have a sense we might now have "concept" caused crashes...why does a commercial airliner need to be FBW? Why use composites to enhance "just enough" engineering? Why create programs that limit/over ride a pilots ability to control his plane in difficult circumstances?
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forgive me for my lack of knowledge with aeroplanes and flights,
But if an airliner suffered engine failure would it be able to glide gentley down like other planes?
An airbus 330 suffered double engine failure and glided (18 minutes) to a successful landing in the Azores so the answer is yes.
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This is the problem here, your attempting to argue that this is a singular event. In 50+ years of commercial jet aviation it hasn't happened ever before (that I'm aware of).
That would make it a singular event. The fact of the matter is, and as stated in the B737 pilot's handbook, had the AA pilot done the same in a B737 the result would have been similar. The rudder was not designed for alternating full deflections, but the pilot did so anyway (and not accidentally, he was trained to do so) and cost 265 people their lives.
The surprise for me is that the alternate law/AP disconnect came 1st. That indicates a massive upset or failure preceding the electrical faults.
In effect leaving the pilots chasing the avionics and then having a situation where it appears that the avionics may have gone totally offline....leaving the pilots with minimal control availability at unusual attitude in IMC in major turbulence...end of story. I'd almost 100% bet a 767 would have had no similar issues here....
Since we know absolutely nothing of what actually happened your bet is as baseless as your arguments so far. Only five A330's have been lost in accidents since its debut in 1991 and only two of those had fatalities (including this latest one). In the same time period eleven B767's have been lost in accidents, six of them with fatalities. About 300 more B767 have been built over the 600 A330's delivered so far, so you'd expect a slightly larger number of accidents, but not more than double. So from a safety record point of view I'd rather fly the A330 than the B767.
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I'm not blaming it on the composite entirely since the underlying design was at fault.
Which design fault would that be?
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I find it rather entertaining how humble's posts are apparently always the "simple truth." Anyways...
1) Is there anywhere ever in the 50+ years of jet age aviation a prior case of pilot induced structural failure at moderate speed?
And what if there isn't? That simply means that no one has thrashed the rudders around so improperly until this guy. You're also disproving your own point; yes, we can only show you one account of this. Does this not mean that the REST of the identical A300s out there have been doing their job and not falling out of the air due to a leadfoot?
It "frightens" you to think that a plane can snap apart by "moderate use" of the rudder. Anything but a fighter jet (and even those at some point) will fall apart with that much shearing force put upon their structure, no matter the material it's made of.
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Which design fault would that be?
Quoting the terrible English at Wiki due to laziness, but it's already been stated.
However, contributing to these rudder pedal inputs were characteristics of the Airbus A300-600 sensitive rudder system design and elements of the American Airlines Advanced Aircraft Maneuvering Training Program. The A300 family has the distinction of having the lightest breakout force and the highest number of degrees of rudder travel per pound of force of any other transport category aircraft. Once a pilot initiates rudder movement, he or she will be challenged with the most sensitive rudder handling qualities of any transport category airplane. This sensitivity is a precursor to a characteristic known as Aircraft Pilot Coupling (APC), a condition typically “…not feasible for a pilot to realize and react to in real time,” and considered unacceptable in U.S. certified designs (National Research Council 15). Simply, a very light application of force coupled with a very small movement of the rudder pedal will yield full deflection of the rudder.
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The Air France A330 apparently flew through the inter-tropical convergence zone; a phenomenon feared by seafarers and aviators alike. This is where two air masses meet, sending huge storm clouds more than 40,000 feet into the sky creating lighting storms with hailstones the size of softballs and sudden mini cyclones.
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Quoting the terrible English at Wiki due to laziness, but it's already been stated.
That is not a design flaw. The aircraft was certified as safe to fly; in other words the sensitivity of the rudder controls were not deemed unsafe, and thus the plane was designed within the safety regulations governing commercial flight. If the pilot had just stomped on one pedal the rudder and vertstab was designed to take it. What it wasn't designed to take was the alternating stomping on both pedals; something few, if any, airliners are designed to tolerate. While the A300-600 had lighter and more sensitive rudder controls than other similar airliners they still required a 35 lbs force for maximum deflection; that's not a hair trigger by anyones standard.
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Anyone know what the airliner's Flight Level was when it failed to make the regular check-in?
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Anyone know what the airliner's Flight Level was when it failed to make the regular check-in?
35,000 feet.
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humble, there is no such thing as "consumer" grade composites.
There are resins and fibers designed to meet specific requirements. Just like specifying any metal alloys to be used. Resins/fibers can also be used to augment metals, and vice-versa.
Most of the expense in resin/fiber construction are in the layup process. It is a very difficult and exacting process. When a mistake is made, you normally have to throw away the entire section and start over.
With metal, not so much.
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35,000 feet.
Seems rather low for an inter-continental flight. Well, then I guess they could have run into some clouds.
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One thing seems to be totally overlooked in this discussion: lightning strike as claimed by Air France.
Here's a major downfall of composites - they're vulnerable to lightning damage where metal will conduct the current away. It's possible a lightning hit caused a catastrophic failure of some composite part as has happened to some composite helicopter blades previously.
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Seems rather low for an inter-continental flight. Well, then I guess they could have run into some clouds.
35k is th A330's rated cruise altitude. I don't know what its ceiling is, probably in the 40's.
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One thing seems to be totally overlooked in this discussion: lightning strike as claimed by Air France.
Here's a major downfall of composites - they're vulnerable to lightning damage where metal will conduct the current away. It's possible a lightning hit caused a catastrophic failure of some composite part as has happened to some composite helicopter blades previously.
While it is true that the metal fuselage protects the occupants from lightning it is a popular myth that aircraft don't take damage from lightning strikes. They do, and a number of fatal accidents are attributed to lightning strikes.
(http://img156.imageshack.us/img156/2562/nosecone2em.jpg)
For example lightning strike caused this Asiana Airlines' A321 nose cone to fall off.
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Is the plane itself struck or does the plane happen to just inadvertently fly into a lightning strike? It doesn't make sense to me that an aircraft with no physical connection to the ground can be struck by lightning seeking the easiest route to the ground.
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I was on a plane flying from rome to pisa and the plane got struck by lightning..it made a big bang and flash..everything was ok :rock
i was flying in a fokker 50 or 100.
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One thing seems to be totally overlooked in this discussion: lightning strike as claimed by Air France.
Here's a major downfall of composites - they're vulnerable to lightning damage where metal will conduct the current away. It's possible a lightning hit caused a catastrophic failure of some composite part as has happened to some composite helicopter blades previously.
I own a Cirrus SR-20 which is 95% composite minus the control surfaces.
An SR-22 was struck by lightening sitting on the ramp in IER (Natchitoches, LA). I have the photos somewhere. There were hundreds of little holes blown out of the skin and a few large areas of damage under the wire mesh. It was ugly. I have no idea if or how it was repaired and what the final outcome was. It looked like the structure was compromised significantly, but without a full inspection there would be no way to know for sure.
I was struck in my Twin Beech right on the nose of the airplane. I was an impressive experience. The bolt looked to be about a foot in diameter and the impact point was only about 8 feet in front of our noses. It was LOUD, too. There was about a four inch diameter burn spot on the radome and we could find no other damage at all. It seems as though the voltage just ran over the surface and discharged out the static wicks.
(http://www.cirruspilots.org/cfs-file.ashx/__key/CommunityServer.Components.PostAttachments/00.00.08.02.73/3_2D00_204957_2D00_DSC_5F00_0333.jpg)
(http://www.cirruspilots.org/cfs-file.ashx/__key/CommunityServer.Components.PostAttachments/00.00.22.70.85/3_2D00_204959_2D00_DSC_5F00_0323.jpg)
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That is not a design flaw. The aircraft was certified as safe to fly; in other words the sensitivity of the rudder controls were not deemed unsafe, and thus the plane was designed within the safety regulations governing commercial flight. If the pilot had just stomped on one pedal the rudder and vertstab was designed to take it. What it wasn't designed to take was the alternating stomping on both pedals; something few, if any, airliners are designed to tolerate. While the A300-600 had lighter and more sensitive rudder controls than other similar airliners they still required a 35 lbs force for maximum deflection; that's not a hair trigger by anyones standard.
This is not entirely true, AA and the pilots association contend (and are still litigating) that the root cause is a design flaw.
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35k is th A330's rated cruise altitude. I don't know what its ceiling is, probably in the 40's.
My first Airbus flight was on the leg London - Munchen with Lufthansa back in 1993. We cruised at 39K. Was one of the best airline flights I ever had. The aircraft had a very good ROC and was quite stable. I think the alt was because of bad weather by the way. After all, it was December.
Anyway, if I understand the theories on the composites, - could it be that the airbus would catch a lightning worse than a metal airframe due to the lack of "skin"? I have no idea really, but neither do I have much ideas about thunderstorms above 39K...
I did get hit by a lightning once, - well it hit the car I was driving. Wham-Bang, and a flash and that was it. No damage visible.
It was a Volvo ;)
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Is the plane itself struck or does the plane happen to just inadvertently fly into a lightning strike? It doesn't make sense to me that an aircraft with no physical connection to the ground can be struck by lightning seeking the easiest route to the ground.
I figure it still has to do with resistance. Lightning is just waiting to happen until it can get enough push to make it through the air to the ground. Although the plane doesn't make the trip to the ground immediate like a big ol' wire would, the metal is much less resistant than air and will make the path "shorter." If the lightning is just about ready to strike and the plane flies under it, bang.
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Skuzzy, "consumer grade" is a relative term. I'm using it in the context of a customer originated purchase decision matrix that balances percieved cost/benefit vs the more absolute performance regardless of cost we see in military development. While the military doesnt have an endless budget and airlines wont intentionally buy "less safe" airframes the reality is that all modern planes (not just Airbus) are effected. The end result is planes designed to maximize revenue and be "good enough".
I can find only one case of a turbulence induced crash in the last 30 yrs (I may very well have missed one){Polkovo 612}. The plane in question was forced over its designed alt limit and apparently entered a flat spin. Numerous distress calls were picked up as the pilots fought for control all the way down.
The lack of any distress signals indicates a sudden and catastrophic failure vs a prolonged attempt to regain control. AF is the source for the order of the automated signals received that indicated AP disconnect and a change in the planes flight logic. From the query I posted on Pprune it appears that the airbus is designed to eliminate fail safes...so a change in "logic" would disable restrictions designed to protect the plane in normal flight to give the pilot more authority over inputs. I have no idea how this interfaces with the ADIRU and how it effected the Quantus flight (and others). I do know that the 612 plane (Tu-154) was largely intact. Just looking at 747's I can find 4 accounts of turbulence severe enough to kill one or more passengers and cause upset severe enough to literally flip the plane on its back in at least one instance. Other instances of upset at cruise due to mechanical failure (china air 006 comes to mind) show a history of planes able to survive severe stress in flight. Another instance is an El Al 747-200 (ferry no pax) that lost #3 pylon engine in flight...which hit #4 which also separated and took off the leading wing edge. The plane almost made it back to point of origin before crashing on final.
I recognize the reality of unforeseeable events and "acts of god". However the reality that its now acceptable engineering for a plane to fail completely in normal use is appalling.
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This is not entirely true, AA and the pilots association contend (and are still litigating) that the root cause is a design flaw.
As the alternative would be training flaw ... what else can they say ?
One thing seems to be totally overlooked in this discussion: lightning strike as claimed by Air France.
Here's a major downfall of composites - they're vulnerable to lightning damage where metal will conduct the current away. It's possible a lightning hit caused a catastrophic failure of some composite part as has happened to some composite helicopter blades previously.
I remember reading somewhere that some metal in the composites just to handle that.
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This is not entirely true, AA and the pilots association contend (and are still litigating) that the root cause is a design flaw.
Again, what flaw? The aircraft was certified, and do you consider 34 lbs of force to be excessively light for full rudder deflection?
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I'm sure every aircraft that's crashed in service was certified.
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I'm sure every aircraft that's crashed in service was certified.
True, and the NTSB did not fault Airbus in this incident. It was clearly pilot error.
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I did get hit by a lightning once, - well it hit the car I was driving. Wham-Bang, and a flash and that was it. No damage visible.
It was a Volvo ;)
I heard they will use volvos to replace the abrhams tank
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I figure it still has to do with resistance. Lightning is just waiting to happen until it can get enough push to make it through the air to the ground. Although the plane doesn't make the trip to the ground immediate like a big ol' wire would, the metal is much less resistant than air and will make the path "shorter." If the lightning is just about ready to strike and the plane flies under it, bang.
That would be a meteorological marvel considering it was at Flight Level 350... I do understand what you're saying, though.
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Why would it be a meteorological marvel? Most lightning discharges between differently charged clouds, only a very few discharge into the ground (or rather up from the ground). A plane flying between two storm clouds is very much at risk at any altitude.
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I'd almost 100% bet a 767 would have had no similar issues here....
But a 777 or (one-day soon - maybe) 787 would have.
I'm not a Airbus fanboy or Boeing hater, just pointing out that composites and FBY are the direction the whole industry is heading in. Airbus just happen to be ahead of the curve a little.
And btw, wouldn't FBW have prevented the A300 crash over NY?
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http://www.weathergraphics.com/tim/af447/
Very good discussion on the weather conditions at the time conducted by a USAF guy who did the forecasting forthe sector between Mombasa, Kenya and Cairo, Egypt for C-5 and C-141 aircraft. I'm posting the text and graphics.
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Air France flight 447 (AF447), an Airbus A330 widebody jet, was reported missing in the equatorial Atlantic Ocean in the early morning hours of June 1, 2009. The plane was enroute from Rio de Janeiro (SBGL) to Paris (LFPG). Speculation suggested that the plane may have flown into a thunderstorm. The objective of this study was to isolate the aircraft's location against high-resolution satellite images from GOES-10 to identify any association with thunderstorm activity. Breakup of a plane at higher altitudes in a thunderstorm is not unprecedented; Northwest Flight 705 in 1963 and more recently Pulkovo Aviation Flight 612 in 2006 are clear examples.
Back in the 1990s I did flight route forecasting for the Air Force. One of my assignments in summer 1994 was forecasting was the sector between Mombasa, Kenya and Cairo, Egypt for C-5 and C-141 aircraft. The Sudan region had tropical MCS activity similar to this with little in the way of sensor data, so this incident holds some special interest for me as one of our C-5s could easily have followed a very similar fate. Using what's available to me I decided to do a little analysis and see if I could determine anything about the fate of AF447 and maybe through some circuitous, indirect means help give authorities some clues on where to look.
1. Reports and evidence
Reports indicate AF447 reported INTOL (S01 21.7',W32 49.9' or -1.362,-32.832) at 0133Z and was to proceed to TASIL (N4 00.3',W29 59.4', or +4.005,-29.990) in 50 minutes (a true track of 28.1 deg) (source) indicating that it flew high altitude route UN873 (see below).
(http://www.weathergraphics.com/tim/af447/af447-route.jpg)
Enroute High Altitude Caribbean and South America H-4, 30 AUG 2007 (National Geospatial-Intelligence Agency)
Though the actual flight plan data was not accessible to me, this corresponds well with an actual flight plan found on the Internet for a Varig B767 from Rio de Janeiro to Frankfurt:
(FPL-VRG8744-IS -B763/H-SIRYW/S -SBGL0110 -N0485F290 PCX3 POKA UA314 NUQ/N0475F330 UA314 SVD UZ10 NTL/M080F320 UN873 FEMUR/M080F320 UN873 INTOL/M080F320 UN873 EPODE/N0476F340 UN873 ASEBA/N0475F340 UN873 SAGMA/M080F340 UN873 CVS/M080F360 UN873 LIMAL/N0463F360 UN873 GDV UN858 SUNID/N0454F380 UN858 DGO UN976 PPN/N0457F360 UN976 LATEK UN871 KUDES T163 PSA PSA2W -EDDF1129 LSZH EDDL -EET/SBRE0050 SBAO0309 ORARO0340 GOOO0355 GVSC0518 GCCC0618 GMMM0746 LPPC0836 LECM0848 LFFF0951 LSAS1042 EDUU1059 EDFF1111 RIF/PPN/N0456F390 UN857 BAN BAN2E LEMD RMK/ETOPS UNDER 120 MIN RULE ENROUTE ALTS SBNT GVAC)
I decided to project the flight forward from INTOL. An altitude of FL350 and speed of 520 mph was given. Presumably this is ground speed according to the ACARS specification. Compensating for a 10 kt headwind as given by the SBFN sounding this yields an airspeed of M.80, which correlates well with the A330's typical early cruise profile. This yields the following aircraft coordinates:
Time Coordinates Description
0133Z -1.362,-32.832 Reported INTOL
0145Z -0.033,-32.125 Extrapolation
0200Z +1.629,-31.242 Extrapolation
0215Z +3.290,-30.357 Extrapolation
0223Z +4.150,-29.876 Estimated TASIL
0230Z +4.951,-29.469 Extrapolation
2. Meteorological analysis
Surface analysis showed the suspected crash region to be within the intertropical convergence zone (ITCZ), which at this time of year is usually found at about the 5-10N parallel. A region of strong trade winds covered most of the tropical North Atlantic and this kept the ITCZ in a somewhat southerly position. The linear convergence along the ITCZ and the unstable atmospheric conditions combined to produce scattered clusters of thunderstorms.
(http://www.weathergraphics.com/tim/af447/af447-sfcanl.gif)
Surface analysis for 0000Z. (NCEP)
Using McIDAS I acquired satellite GOES-10 satellite data from UCAR and centered it over the region between INTOL and TASIL. I then plotted the waypoints using McIDAS's built-in coordinate entry panel. Since the source satellite images are georeferenced NOAA/GINI datasets, the points shown here are very accurate and are NOT placed by hand but by lat/long coordinates to the nearest 0.001 deg (0.06 mile). In the image below, the stationary southerly point in blue is INTOL and the aircraft's estimated location from the above table is marked with a cross. Graticule spacing is 5 degrees. For the orange temperature plots I used the NCL/3aw curve; the sharp gradient of the enhancement from dark to light occurs at 243K (-30 deg C), indicating a cloud top of FL310 assuming the satellite pixel is completely overcast with that layer (which is not always true).
(http://www.weathergraphics.com/tim/af447/af447-0230-temp.jpg)
(Hit reload if you don't see the satellite images in the looper above)
Raw infrared images are also available here: 0145Z, 0200Z, 0215Z, 0230Z.
And finally this image shows a zoomed image at 0215Z when AF447 made its last transmission:
(http://www.weathergraphics.com/tim/af447/af447-0215-zoom.jpg)
About 90% of the cloud material seen on this image is actually multiple levels of convective debris fields from dying storms and activity that occurred previously during the day, with only scattered cirrus fields at flight level. The active thunderstorm areas are defined by small-scale mottled areas of cold cloud tops. Compare with this structural diagram below of a similar tropical MCS in the same area in 1977. It illustrates that planes inflight are clear of most dangerous weather throughout a tropical system except when directly above an active updraft area.
(http://www.weathergraphics.com/tim/af447/af447-conceptual.jpg)
Schematic of a typical tropical MCS observed in the Atlantic southwest of Dakar on 4 Sep 1974. (Structure and Dynamics of a Tropical Squall-Line System, R. A. Houze Jr., Mon. Wea. Rev., 105, 1540-1567)
It appears AF447 crossed through three key thunderstorm clusters: a small one around 0151Z, a new rapidly growing one at about 0159Z, and finally a large multicell convective system (MCS) around 0205-0216Z. Temperature trends suggested that the entire system was at peak intensity, developing rapidly around 2300-0100Z and finally dissipating around dawn. From a turbulence perspective, these cold spots would be the areas of highest concern as they signal the location of an active updraft producing new cloud material in the upper troposphere.
The last communication from the plane was at 0214Z (12:14 am local meridian time). This was an automated ACARS message reporting an electrical fault and pressurization problem. This would be about the time the plane was beginning to exit the cluster, but not before having flown for 75 miles of numerous updrafts. The exact aircraft location cannot be determined with certainty, however, since a 1-minute time error in position or reporting time translates to 9 miles of spatial error.
The Fernando de Noronha sounding is available here and shows typical tropical conditions with modest positive energy throughout the column from the surface up to 45,000 ft. There is what looks like anvil level material above 25,000 ft. The significant dry mid-level air is somewhat unusual and suggests the potential for enhanced evaporational cooling in the upper troposphere enhancing downdraft production, and any synoptic-scale lift (if present) enhancing instability through adiabatic cooling of the layer.
I modified this sounding (see below) using the prevailing temperature/dewpoint field across that part of the ocean and modifying for some cooling due to nighttime loss of heating. This is my best guess at the parcel profile that fed this storm. It yields a worst case instability of 1048 J/kg of CAPE, which is moderately strong but considered borderline for typical severe weather. Vertical velocity can be obtained by w=2*CAPE^0.5 yielding a maximum possible updraft speed contribution of 45.8 m/s or 102 mph, though in reality this is usually much less (on the order of half or less) due to precipitation loading and other factors.
(http://www.weathergraphics.com/tim/af447/af447-skewmod.gif)
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3. Conclusions
The satellite imagery indicates that numerous cumulonimbus towers were rising to at least 51,000 ft, and were embedded in extensive stratiform anvils with tops of 35,000 to 45,000 ft. This kind of configuration is actually quite normal for equatorial storms due to the higher tropopause height, but it emphasizes that the aircraft was certainly within the bulk of an extensive cumulonimbus cloud field for a significant amount of time and that storms could indeed have been a contributing factor to the crash.
I've edited this section Monday night to cut down on the speculation about the accident chain, especially since I don't know a whole lot about A330 systems. The airliners.net board and other sites cover the aircraft and CRM systems quite well. What I will try to do, however, is summarize what the aircraft probably encountered based on the data and my own experience.
* Turbulence -- Turbulence is a definite candidate as a contributing factor. There is an isolated storm at (1.6,-31.5) that appears suddenly at 0200Z just as the A330 enters the main MCS cluster. From a turbulence perspective it is by far the most dangerous formation found on the loop. However it is 10-25 km to the left of UN873 and it is doubtful the crew would have been deviating at this time. Other cells like this one embedded within the main MCS may have caused severe turbulence. Young updrafts are particularly dangerous to flights because they contain significant rising motion yet precipitation fields have not yet fully developed and airborne radar signatures are weak, reducing the likelihood the crew will deviate around the cell. Another concern is the extensive upper-level dry air shown on the SBFN sounding (not counting the anvil debris at 350-300 mb), which may have contributed to enhanced evaporative cooling in and around the anvil and aggravated the turbulence experienced by the flight, especially around the margins of anvil clouds and towers. It is worth considering that cumulative periods of heavy turbulence crossing through the cluster may have caused minor internal damage that progressed in some way into an emergency.
* Icing -- With a flight level temperature of -43 deg C suggested by the proximity sounding the A330 would have been flying mostly in rime ice and possibly some clear ice and graupel. At -43 deg C, water cannot exist even in supercooled form (see here for an explanation). The equivalent potential temperature throughout the profile is absolutely insufficient to bring warmer air with supercooled water to flight level. Without the supercooled water there is very little ice buildup on the airframe. My conclusion is that unless the plane descended below FL300 icing would not be the culprit.
* Lightning -- Due to the high cloud tops and freezing level at 16,000 ft, there was extensive precipitation by cold rain process and it is likely the MCS was electrified. Lightning of course being considered with good reason since the A330 is one of the most computerized and automated airliners in service. I will say based on my 25 years of meteorology the storms were almost definitely producing lightning. As far what a strike would do to the A330, I have to leave that to to the avionics experts. Some answers might be found at http://www.airliners.net/aviation-forums/.
* Precipitation -- A dual engine flameout due to precipitation or ice ingestion is a noteworthy possibility as has been discussed on other sites (specific to the A330 type too). The precipitable water content in any tropical weather system can run very high. However a rain-induced flameout is not possible because supercooled water cannot exist at the -43C cruise altitude and insufficient equivalent potential temperature exists, even in updraft cores, to bring warmer air beyond a few degrees change to the flight level. Therefore the plane at FL350 was completely within some mixture of rime ice, graupel, or small hail. But again, as the link indicates, even ice poses risks to the engine.
* Hail -- I got a few comments about hail. I am not entirely convinced that structural hail damage is a factor, partly because I can't recall hearing much about large damaging hail at altitude in my experience with equatorial flight operations. This would require strong instability, which I'm not yet sure we have, not only to grow the stones but to loft large hailstones from the embryo "nursery" at FL200-250 up to flight level. A value of 1000 J/kg CAPE is really on the fence but not out of the question. The other problem is the mounting body of evidence (see SPC studies) suggesting well-sheared storms (this profile is poorly sheared) are the ones conducive to structures that support hail growth. Finally, another issue is airborne radars are be highly sensitive to hail because of the very high backscatter values of ice, making evasive action likely, and the "young updrafts" I pointed out earlier as a threat would not have provided the residence times necessary yet to contain hailstones; their main threat would be severe turbulence. I am not sure about the hail hypothesis, but I believe there is a high probability of graupel, small ice pellets, or small hail at FL350 in the storm complex (see Icing above).
Overall what we know for sure is weather was a factor and the flight definitely crossed through a thunderstorm complex. There is a definite correlation of weather with the crash. However the analysis indicates that the weather is not anything particularly exceptional in terms of instability or storm structure. It's my opinion that tropical storm complexes identical to this one have probably been crossed hundreds of times over the years by other flights without serious incident.
Still, in the main MCS alone, the A330 would have been flying through significant turbulence and thunderstorm activity for about 75 miles (125 km), lasting about 12 minutes of flight time. Of course anything so far is speculation until more evidence comes in, and for all we know the cause of the downing could have been anything from turbulence to coincidental problems like a cargo fire.
My own opinion of the crash cause, as of Monday night, based on the complete lack of a HF radio call and consideration of all of the above, suggests severe turbulence (see the BOAC 911 and BNF 250 tragedies) combining in some unlikely way with CRM/design/maintenance/procedural/other deficiencies to trigger a failure cascade. We can almost certainly count on some unexpected surprises once the CVR is recovered. Until then, all we can do is await the investigation and hope that the world's flight operations stay safe until AFR447's lessons are revealed.
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Good read. Thanks!
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Nice write up Wolfala. Im going for the Catastrophic Failure myself, with a possible ADIRU glitch as per the QANTAS incident a few months ago.
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just wondering, does this sort of stuff make you nervous JR?
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While it is true that the metal fuselage protects the occupants from lightning it is a popular myth that aircraft don't take damage from lightning strikes. They do, and a number of fatal accidents are attributed to lightning strikes.
(http://img156.imageshack.us/img156/2562/nosecone2em.jpg)
For example lightning strike caused this Asiana Airlines' A321 nose cone to fall off.
Wasn't this a radar nose cone made out of composite?
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just wondering, does this sort of stuff make you nervous JR?
Mate, it used to, but now these sorts of things are 1 in a millon events, I cant win lotto, so the best I can do is learn from tragedy's like this, and pray that Im not in that situation.
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Mate, it used to, but now these sorts of things are 1 in a millon events, I cant win lotto, so the best I can do is learn from tragedy's like this, and pray that Im not in that situation.
Worry about it when you win lotto
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WOW Wolfala.
"The satellite imagery indicates that numerous cumulonimbus towers were rising to at least 51,000 ft, and were embedded in extensive stratiform anvils with tops of 35,000 to 45,000 ft. This kind of configuration is actually quite normal for equatorial storms due to the higher tropopause height, but it emphasizes that the aircraft was certainly within the bulk of an extensive cumulonimbus cloud field for a significant amount of time and that storms could indeed have been a contributing factor to the crash."
51K! No way to cruise over that. As a pilot, I'd probably chicken out and RTB. All pilot hate Cumulus.
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Latest speculations are about a terrorist attack. Turns out a previous flight had a bomb threat that grounded the plane for a while.
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interesting discussion :aok
As for composites vs alloys, you design for whatever requirements you have, composites just give you a different range of options. Good engineering is about choosing the best compromise, like Colin Chapman said about materials "Strong, light, cheap - pick any 2"
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It'd be ironic if the plane went down from bad weather before such a terrorist had begun his attempt.
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Wow, that would be hilarious. :lol
I think if it were a terrorist attack the party responsible would have taken responsibility (fame and glory).
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Wow, that would be hilarious. :lol
I think if it were a terrorist attack the party responsible would have taken responsibility (fame and glory).
Umm.. nothing hilarious about 200 people getting killed on their holiday trip regardless of how it happens. Could have been you or me sitting there.
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I never implied that their deaths would be hilarious. I implied the occurrence of the plane striking water before the terrorist could cause it would have been hilarious.
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New speculations:
The A330 has had 4 incidents involving ADIRU failures. The flight computer has been receiving corrupt data and in the latest Qantas case the plane dived uncontrollably for 20 seconds after flying for 3 hours. Several passengers got injured by negative G's.
If the malfunction happened in middle of a thunderstorm it might easily overload the airframe and game over..
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Eeek! That doesn't sound good. Wouldn't that also mess up the instrument's feedback in the cockpit? So if they did go manual their main instruments would have been of no use.
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New speculations:
The A330 has had 4 incidents involving ADIRU failures. The flight computer has been receiving corrupt data and in the latest Qantas case the plane dived uncontrollably for 20 seconds after flying for 3 hours. Several passengers got injured by negative G's.
Supposedly this is not true. The procedure has since then been altered on all planes using the same model of the ADIRU unit. Although the issue still awaiting for a final fix, but the current modifications are said to be enough to prevent it from happening again.
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This AF A330 has different ADIRU unit(s) & software from the QF A330 manufactured by different companies.
Also remember ADIRU incidents are not just an A330 problem as per the MH B777-200 in 2005.
Tronsky
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Airbus issues go far beyond the ADIRU. At the heart of the issue is a fundamental conceptual difference between Airbus and Boeing. Boeing designs planes for pilots and Airbus designs planes for accountants. Neither philosophy is automatically wrong and no question that the recent buffalo accident was much less likely in an "airbus configured" environment. Issues specific to the AF crash point more and more to an in flight upset then anything else. He (captain) was high and fast in a heavy plane in bad weather.
At reduced speed for turbulence penetration he had minimal speed protection vs stall and yet only a small operating window to over speed. This "coffin corner" of the flight envelope is a deadly place for any plane. My understanding is that once an overspeed condition reaches 6 knots the AP disconnects and alternate law precludes certain inputs to protect against further overspeed, basically allowing the plane to climb to avoid further speed increase. So a strong updraft might carry the plane higher further minimizing the speed range for safe flight, if the plane is flown manually then certain inputs are dampened until overspeed is corrected....but this can leave the plane higher then planned under manual control but with none of the flight protections the airbus relies on working. So a pilot conditioned to have the avionics smooth out any excessive input will suddenly be without protection in a very dicey situation.
This is potentially compounded by the very complex nature and fault prone avionics in the airbus. In effect you have a 100 variations of "what is it doing now" in play every day around the world. Only the worst ones reach the public ear.
This is a Prune comment from an Airbus driver...
I've seen tops above 60,000 ft at the equator. Accidental penetration of shorter columns can be violent. On the A310, you can loose both tat probes and loose Sat for a time with ice. This happened to us once going through a benign looking arm of weather a hundred miles from a typhoon near Borneo. The yaw dampers popped off followed by the autopilot. The Airbus autothrottles went bezerk so had to disconnect those. All airspeed was lost. It got very noisy from HAL screaming about wind shear and other incorrect imagined problems. All three Altimeters disagreed so we didn't know which was right. A few minutes later in clear wx everything came back. Like nothing happened!
My theory: I never had this happen in any boeing or douglas aircraft. I beleive airbus probe heating is occasionally weak (again, just compared to boeing.) I feel airbus automation actually increases pilot workload (AW&ST) Aug 1995, which is of course, exactly the opposite of how this equipment was originally marketed.
Composite tails are a concern also. FAA certification does not require full deflection capability in both directions I was told as was the case with AAL A300 in New York attributed to pilot error. Old Boeing iron however, has this capability: engineering far exceeding the minimum FAA certification specification. A few 747 era Boeings and DC-8's survived jet upsets that resulted in supersonic dives. I'm not sure todays composite airframes could do it? Are you?
These are just my opinions only. I never flew the A330.
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At the heart of the issue is a fundamental conceptual difference between Airbus and Boeing. Boeing designs planes for pilots and Airbus designs planes for accountants.
got to disagree here snap, the market determines the design so both Boeing and ABI design planes for the operators. same market, same requirements. the engineering expertise and production costs are comparable either side of the pond, which means that if Boeing aircraft were massively overengineered compared to ABI aircraft, the operating costs would be that much higher and no one would buy em. certainly they have different approaches to their designs, but the differences arent that massive.
I'm quite surprised by the wariness of FBW systems some people here have, if FBW is inherently unsafe and makes aircraft more difficult for experienced pilots to operate, someone should tell the 1000s of pilots who've been flying F-16s for the last 30 years ...
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The conceptual differences in design philosophy are very very real. The Airbus is engineered to the lowest common denominator with the avionics intent on preventing "bad piloting" and designed to over ride "improper" pilot commands. The Boeing is designed to guide the pilot but will not prevent a pilot from being stupid. Airbus has pioneered cost oriented engineering and dragged Boeing along for the ride. Not all of this is bad, simply different. Where it gets ticklish is that a lot of engineering is balancing safety vs cost (both build and operational).
FBW was originally designed to enable military pilots to fly airplanes that might not be flyable with "normal" controls. The computer "translates" normal control inputs into more complex ones required to fly the aircraft. For many cutting edge planes FBW is the only way to fly. This technology has been utilized by airbus as a sales feature. The simple reality is that its a lie. FBW is not simpler or safer and does not reduce pilot workload....end of story. It will without a doubt eliminate some very real % of pilot induced accidents, at the expense of a greatly complicated work environment when things go "tits up"....
Here is another pprune post from an airbus driver....
I take the liberty of posting my previous message again, if I may...
Although the initial failure report in the automatic message seems to have been about electrical problems (I do not know which) and the "tree" of possibilities of systems degrading from there is a vast one, I have kept in mind since the sad news ot the accident the following facts:
the A330 is a beautiful aircraft but it has shown, again and again , very susceptible to probes icing, with the deicing system on auto (numerous reports). This leads to very rapidly presenting the crew with a very lame aircraft to say the least (I give you a factual example below, recent, on an A330, without comments). This has happened at high cruise altitudes, with no ICE alarm, with the heating on AUTO, and out of clouds in some cases...
"Light tutbulence. The speed indication on the right PFD falls suddenly from 280 to 100 knots in red tape for a few seconds Almost immediately the speed on the left PFD falls to green dot minus 15 knots with a speed trend of minus 50 knots. Red alarm A/P OFF ADR
DISAGREE, IAS DISCREPENCY, ALTN LAW PROT LOST, REAC W/S DET FAULT.
Then amber alarm RUD TRV LIM FAULT.
Then STALL STALL STALL with Toga Lock indication.""
The crew changes flight level, the captain pilots with the stand by instruments,
The speeds become normal again.
The status after that:
amber crosses on PFDs
W/S DET FAULT, ALT LAW PROT LOST, ADR DISAGREE et F/CTL RUD TRV LIM FAULT (2
NOGO).Plane in Alternate law
This shows how an unconfortable event (loss of airspeed indication) that would have been minor in, say , an A300, becomes a major headache in those very sophisticated cockpits. Just for information and not saying that is
a possible explanation...but lose electrics, and apart from dealing with retrieving the generators, you may have that kind of thing loaded on top...
This failure has happened not once but at least four times in the previous year on the fleet.Why do heated pitots ice? In non severe icing conditions, and even out of clouds?I have flown a lot and I would have said that was impossible but the facts are there. It is a documented fact at least on this type of aircraft.We learn from facts and this could very possibly have a direct bearing to this tragic accident.
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Supposedly this is not true. The procedure has since then been altered on all planes using the same model of the ADIRU unit. Although the issue still awaiting for a final fix, but the current modifications are said to be enough to prevent it from happening again.
The problem isn't specific to the ADIRU, while that type of incident would cause massive problems in a thunderstorm and turbulence you cant find 100's of other incidents of the avionics disconnecting AP kicking the plane into alternate law. This causes significant work load and deprives the pilots of exactly the protections they rely on in flying the various airbuses.
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The problem isn't specific to the ADIRU, while that type of incident would cause massive problems in a thunderstorm and turbulence you cant find 100's of other incidents of the avionics disconnecting AP kicking the plane into alternate law. This causes significant work load and deprives the pilots of exactly the protections they rely on in flying the various airbuses.
But the real question is what makes you so biased? You work for Boeing or is it just patriotism?
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I'm not biased in any way.
Both plane sets have their share of issues and can be complex and unforgiving. Since Boeing was the established industry leader Airbus had to differentiate itself in order to gain market share. As a result certain fundamental differences exist. The reality is that those differences have to some degree polarized the pilot community. While many are comfortable in either set some are very adamantly pro Airbus or pro Boeing.
My "issues" are simple. I'm a firm believer in the KISS principle and complexity for marketing value is a bad idea. The mere fact that you need 3-4 backup systems is a sure indication your heading down a bad rode IMO. Imagine if all the cars on the road had FBW instead of steering linkages. Add to this the inherent issues in tinless solder and its documented effects on computers and other electronics and you have an even more flawed environment. Compound this with the variable logic modes driving the avionics that degrade the protections engineered into the plane and create additional potential issues. The reality is that the airbus appears to be overly complex and at times counter intuitive.
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Humble, just because I am interested and you said both planeset have their issues and can be complex and unforgiving. What do you Boeing's issues are or what could they improve? It has been an interesting discussion on FBW, composites and resins so far .. so I am just curious as to where you can see Boeing has issues.
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Uhmm, humble, without fly-by-wire, the F-16 would have never gotten off the ground. FBW can do a lot of things for the pilot to ease the load of flight. The F-16 is a shining example of FBW done right, in my opinion. In the 30 years of F-16 production, not one aircraft has been lost due to anything related to FBW. Make no mistake about it, FBW in the F-16 is keeping the pilot alive.
The throttle on most cars today is FBW. I have a few hundred thousand miles on those systems myself and have never had a failure of any kind. There has never been a problem at all, as a matter of fact.
Stating all FBW is bad is like saying all cars are bad because of the Yugo.
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Uhmm, humble, without fly-by-wire, the F-16 would have never gotten off the ground. FBW can do a lot of things for the pilot to ease the load of flight. The F-16 is a shining example of FBW done right, in my opinion. In the 30 years of F-16 production, not one aircraft has been lost due to anything related to FBW. Make no mistake about it, FBW in the F-16 is keeping the pilot alive.
The throttle on most cars today is FBW. I have a few hundred thousand miles on those systems myself and have never had a failure of any kind. There has never been a problem at all, as a matter of fact.
Stating all FBW is bad is like saying all cars are bad because of the Yugo.
Thats exactly what I was trying to say here Skuzzy...
FBW was originally designed to enable military pilots to fly airplanes that might not be flyable with "normal" controls. The computer "translates" normal control inputs into more complex ones required to fly the aircraft. For many cutting edge planes FBW is the only way to fly.
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But you also said the following.
My "issues" are simple. I'm a firm believer in the KISS principle and complexity for marketing value is a bad idea. The mere fact that you need 3-4 backup systems is a sure indication your heading down a bad rode IMO. Imagine if all the cars on the road had FBW instead of steering linkages.
This seems to imply you think FBW is just a bad idea all around as it violates the KISS principle and you do not think it can handle simple steering chores in a car, yet they have no problem handling the throttle, which is a more complex system.
Look at my car. It has no air meter. The throttle pedal activates some type of variable resistor, sending its values to the computer. The computer takes those values and adjusts the air flow by altering the amount of valve lift and duration, then also adjusts the duration of the direct injector firing time. It has to do all these things thousands of times a second and not miss a beat or problems could arise.
Steering would be done as follows. The computer reads the resistor value inputs from the steering wheel, then outputs the pulses to a servo control motor to activate the steering mechanism. Now, do you trust a servo control motor anymore or less than the power steering pump?
I am just playing devils advocate to your analogy. I realize it could have been a different one.
I may be wrong on this, but seems to me a good FBW system, in an airplane, is probably the simplest system you can have in terms of number of components and weight. I see no violation of the KISS principal.
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I have 1000 hours in FBW airplanes and the redundancy built into the systems had me more than satisfied to feel completely safe during those operations. Including traversing the Amazon, over water and in the best/worst of weather.
To lose all control capability requires such a huge number of things to go wrong that you're screwed long before you get to the fact your can't control the airplane.
Before we get all hussy over the fly-by-wire aspect that enough here clearly do not understand don't forget that we don't know anything about this accident beyond the airplane is in the ocean. FWIW the only flight control failure I've exerpienced came in an aircraft with cables, pulleys and pushrods. A rudder cable pulley decided to throw in the towel which threw the rudder and aileron controls out of whack due to an interconnect system with the airplane. This resulted in an uncommanded aileron input and a significant roll rate with a very high force required to counter it. After verifying the ailerons were in fact still attached and moving freely using full trim into the roll lessened the force required to maintain wings level.
No such thing has/could/would happen with a fly by wire airplane. In my case there was triple redundancy of the hydraulic systems, the redundancy of the computers as to which electrical and hydraulic system power which actuators including the RAT (Ram Air Turbine) should your emergency degrade to that point you still were afforded with workable flight controls. The airplane was very much overengineered (by Boeing engineers who in effect built the airplane like an Airbus no less) and I found it to be reliable while maintaining a very comfortable level of redundancy for the unfortunate eventualities.
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Humble, just because I am interested and you said both planeset have their issues and can be complex and unforgiving. What do you Boeing's issues are or what could they improve? It has been an interesting discussion on FBW, composites and resins so far .. so I am just curious as to where you can see Boeing has issues.
The reality is that most of what Airbus is pioneering is customer (airline) driven, both in regard to safety and operational affordability. I have no ability to discuss the economic metrics but the flight safety issues are readily observable. Lets look at the two recent crashes (yes the -8 is not a Boeing plane). Both the Buffalo crash and the turkish 737 are a combination of pilot workload, inexperience and potential issues (mechanical, icing etc). The end result is that the pilots action and inaction directly contributed to the crash. As mentioned above somewhere "pilot error" is an ever increasing factor in a majority of air frame losses. The 737's lack of an "alpha floor" and auto throttle clearly contributed to the crash. The colgan FO's pitch setting contributed heavily to the buffalo crash. My understanding is that in normal mode the avionics in the airbus series would have prevented both incidents. So we have the very well intentioned efforts to protect airlines from both the deterioration in experience and training in the potential new hire pilot pool and the reality that ever increasing congestion creates a tremendous pilot workload and creates the potential for a pilot to get behind the plane for numerous reasons.
My "issue" here is the combination of technology in design and concept that attempts to deal with real issues via ever more complex solutions. Pilots rely on avionics in both plane sets way to much. Boeing (correctly IMO) draws the final line of responsibility clearly with the pilot. However we can see that this choice does contribute indirectly to crashes.
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The colgan FO's pitch setting contributed heavily to the buffalo crash.
The what? You really don't have any informed clue about that accident. I could go on for pages about it but suffice to say the blame for the Colgan accident lies squarely on the shoulders of a blabby captain who through the course of the flight caused the crew to be behind in their housekeeping.
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Humble, unlike the F-16 the Airbus' are not inherently unstable designs. In the event of a total electrics failure an Airbus will still fly along quite happily... Of course, it will fly where it wants to go rather than where the pilots would like, but that's no different than in a conventionally controlled airliner. Large airliners need servo power to move the control surfaces, and the electrics power the hydraulics. Wether fly by wire or not you need power to operate the control surfaces. In a conventional aircraft you push the stick and it pushes a hydraulic cylinder which moves the surface; in a FBW aircraft you move a small computer control that tells the computer to move the hydraulics. In either case without power to the hydraulics the surface isn't going to move. To move the surfaces on a 747 with old fashioned wires and the strength of the pilot, as in a Cesna, would require a tug-of-war team on the flight deck.
The chance of a total loss of electric or computers is infinitesimal compared to the chance of pilot error. The NTSB reckons that half the accidents in civil aviation are caused by human error... Half! The computers not only adds a layer of protection against common pilot errors, but also aid the pilots in controlling the aircraft under unusual circumstances such as engine failures and partially or even complete hydraulic failures where the computers will help the pilots control the aircraft with engines and whatever controls remain.
It is my opinion that, even if the computers add complexity and probably will lead to some equipment related accidents, they are worth it for the lives they save by preventing human errors and helping the pilots overcome (even previously hopeless) problems.
http://www.youtube.com/watch?v=xPt0rMVbTmk
http://www.youtube.com/watch?v=s-zqo2QpIC0
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"Fly by Wire" is not driven by the replacement of mechanical linkages with electronic ones (although that is a potential issue) but by the interrelationship between the control surface, control input and the software itself.
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...Boeing (correctly IMO) draws the final line of responsibility clearly with the pilot...
Out of curiosity, is this the case with Boeing's FBY models? Or does the system in the 777 have the authority to override the pilot in a similar maner to an Airbus?
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Some details leading up to the crash have been revealed:
http://www.telegraph.co.uk/news/worldnews/europe/france/5444168/Air-France-pilots-battled-for-15-minutes-to-save-doomed-flight-AF-447.html (http://www.telegraph.co.uk/news/worldnews/europe/france/5444168/Air-France-pilots-battled-for-15-minutes-to-save-doomed-flight-AF-447.html)
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Out of curiosity, is this the case with Boeing's FBY models? Or does the system in the 777 have the authority to override the pilot in a similar maner to an Airbus?
The computer in the Airbus do not have authority over the pilots unless the pilots so chose. The pilots can set the computers to give them full control; if a pilots wants to he can still over stress an Airbus.
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Some details leading up to the crash have been revealed:
http://www.telegraph.co.uk/news/worldnews/europe/france/5444168/Air-France-pilots-battled-for-15-minutes-to-save-doomed-flight-AF-447.html (http://www.telegraph.co.uk/news/worldnews/europe/france/5444168/Air-France-pilots-battled-for-15-minutes-to-save-doomed-flight-AF-447.html)
I'm not so sure I believe the "source". The pilots would have reported problems if they were having cascading systems failures over a period of 15 minutes.
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The computer in the Airbus do not have authority over the pilots unless the pilots so chose. The pilots can set the computers to give them full control; if a pilots wants to he can still over stress an Airbus.
Not true, the only time a pilot has full authority would be in direct law, this is far beyond "pilot choice"....
There is no pilot option to select direct law in any airbus that I am aware of...
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The what? You really don't have any informed clue about that accident. I could go on for pages about it but suffice to say the blame for the Colgan accident lies squarely on the shoulders of a blabby captain who through the course of the flight caused the crew to be behind in their housekeeping.
A lot of factors contributed and in the end the decision to override the stick pusher is baffling. Neither pilot was really qualified to fly a commerical airliner of any flavor IMO. However the decision to set the control lever to max and "flat plane" the props is highly questionable given the need to keep the plane fast. As it relates to my earlier comments the entire point of the airbus software is to preclude pilot induced upset or to override or ignore pilot input and if needed respond to a lack of input....
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It is my opinion that, even if the computers add complexity and probably will lead to some equipment related accidents, they are worth it for the lives they save by preventing human errors and helping the pilots overcome (even previously hopeless) problems.
The problem here is that your incorrect, in an emergency the avionics in the airbus provide no help and might make an upset more likely or recovery from an upset impossible. We certainly do not know what happened but I think its very probable that "normal flight law" might have contributed to creating the upset and that alternate flight law may have precluded recovery...thats not coming from me its coming from guys who fly the 330 for a living...
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Reading PPRuNe doesn't make you a defacto expert. Being able to copy and paste someones opinion doesn't qualify it as your experience.
That said regarding the Buffalo crash I still don't follow what you're trying to say with "the FOs Pitch Setting"
Outside the recline of her seat there's nothing that makes sense. The condition, propeller and power levers all belong to the flying pilot. It is standard to increase the propellers to full rpm for landing however those engines require a power increase because without the extra torque you just put two efficient drag discs onto your airplane with them in full rpm.
Humble your talking about the various control laws of the Airbus (which you appear not to have a thorough understanding of nor any experience with) is akin to discussion the turn radius of the Zero over a Spitfire during the aftermath of the Pearl Harbor attack.
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I'm not biased in any way.
That's the same as saying, "Nazis have nothing against Israelis!"
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Not true, the only time a pilot has full authority would be in direct law, this is far beyond "pilot choice"....
There is no pilot option to select direct law in any airbus that I am aware of...
All seven computers can be turned off in flight. You only need to shut down a couple though to get direct law.
Even if ALL the computers fail the pilots still have direct engine control, and hydraulic control of the rudder for lateral control, and also hydraulic control of the stabilizer trim through the trim wheel for vertical control.
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So why was the FO manipulating them...and why was power not added. This is exactly the point behind the logic driving the airbus. This is clearly a contributory piece of the puzzle. The FO should not have changed the condition lever without calling it out and not without specific orders. If condition lever to max was SOP on gear down then she still should call it out and the PF should respond with the correct power setting. If the FO does not hear/see/verify the change in power settings then she should have been monitoring the aircraft speed and calling it out as a reminder....or am i wrong here.
I dont know if 50% of the guys flying the 330 fully understand its intricacies. I have absolutely no problem saying that both the operation and logic is baffling to me.
What does appear to be pretty clear is that the potential for the avionics to create serious confusion and potentially cause control issues is very real and specific to the airbus family.
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That's the same as saying, "Nazis have nothing against Israelis!"
Thats an uncalled for comment....
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I'm not claiming to be a "defacto" anything. I'm simply asking a few questions and making a few observations. To summarize:
1) the 300 has a clear design deficiency specific to control surface authority for the rudder
2) composites do not make a plane inherently safer
3) engineering for accounts is an unacceptable risk
4) if you have to try and engineer stupidity out of the flight deck get better pilots
5) if you want a guy to ride with training wheels dont take them off when he really needs them.
A tremendous amount of this makes no sense (AF crash). No reason for them to be there, multiple planes had no problems transversing the same area. The spanish plane was actually 5 min behind them on the same track at a higher flight level (37,000). The only fact we know for sure is that the AP kicked off and things got ugly quickly. So we have an experienced crew in a state of the art plane and in less then 5 minutes afterward they were apparently dead. At this point all roads appear to lead back to the flight control system.
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I'm glad the NTSB and other investigative agencies don't work like you do.
You're dealing purely with speculation without any hard facts whatsoever.
Your knowledge of the happenings of the Buffalo crash is questionable.
You've done it before.
I'm not continuing a conversation because you're not interested in a discussion based on sharing knowledge or experiences but rather hyperbole and waving a few little factoids you've picked up along the way. So far we've gone from one unexplained accident for which we have no hard facts (if you're getting your "facts" from the news agencies there's half your problem) to talking about numerous accidents none of which have any obvious correlation with this one. Thunderstorms in/around the equator are nothing to be trifled with and even the most modern airliner is subject to the limitations of what mother nature can do. You cannot engineer out all risk in aviation and attempting to cover up an opportunity to type facts to show off what you think you know as an educated discussion is pointless.
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Yup.
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They can, but not for long and not without incurring damage, and eventual failure. What you feel during take-off and landing is at most 1.5G. 2.5G is actually a lot more than most virtual "pilots" think.
i think(but not sure) way back when, a CFI had me doing 50-55 degree banked turns in a 172. he said that was about 2 to 2.5G. it was awhile ago, so i'm not sure......
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A 60º turn in level flight will put 2G's on the airplane.
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A 60º turn in level flight will put 2G's on the airplane.
got it....it wasn't then. i couldn't remember what he had said......i do remember we didn't go past 55 though.
i used to have trouble with the steep turns, so he had me do them at that angle.....thus making it easier for me to do them at 45.
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I'm glad the NTSB and other investigative agencies don't work like you do.
You're dealing purely with speculation without any hard facts whatsoever.
Your knowledge of the happenings of the Buffalo crash is questionable.
You've done it before.
I'm not continuing a conversation because you're not interested in a discussion based on sharing knowledge or experiences but rather hyperbole and waving a few little factoids you've picked up along the way. So far we've gone from one unexplained accident for which we have no hard facts (if you're getting your "facts" from the news agencies there's half your problem) to talking about numerous accidents none of which have any obvious correlation with this one. Thunderstorms in/around the equator are nothing to be trifled with and even the most modern airliner is subject to the limitations of what mother nature can do. You cannot engineer out all risk in aviation and attempting to cover up an opportunity to type facts to show off what you think you know as an educated discussion is pointless.
Pardon me, do you actually read what I posted....and have you read the NTSB report on buffalo? The only reason they were mentioned by mew was to point out the pilot related issues that airbus is trying to address. FYI the FO not the PF moved the condition lever and did not call it out. The PF did not adjust power settings and apparently neither one was scanning so the plane fell out of the sky. The alpha floor in the airbus is specifically designed to deal with this type of issue....or am I wrong here.
The faults are out in the french media for those with interst and a better technical grasp...
(http://i337.photobucket.com/albums/n385/motidog/AF447-ACARS_1.jpg)
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I certainly do not have any ability to really decode them but found it intriguing that the 1st (or last) fault was rudder related...
Reads from the bottom up, so AP disconnect was the 1st, and last was rudder travel (in the initial burst).
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Humble, how "much" control do you want from the plane in normal law? Normal law gives you 66 degrees of bank and the pitch is available (to what degree, im not sure without looking at the books) where it would be uncomfortable for all. The speed brake is full available. One click of the auto throttles gives you full command of the thrust. As I see it, everything that you could expect is available to you.
The crux of the matter we dont know whether it was the design of the plane that led to the crash, certainly a contributor, but who is to say if it was a 777 that it would not ended the same way?
We're debating variables over facts unknown.
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We're debating variables over facts unknown.
And thats the key, especially a theory the A330 is an inherently dangerous airplane as a primary fault of this crash seems a tad pointless, especially an aircraft that is over a decade old...as are most "theories" until more real "actual" information is made public
Tronsky
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I heard/read that the wreckage thay was found does NOT belong to the Air France A330.
http://amfix.blogs.cnn.com/2009/06/05/expert-investigators-blind-without-wreckage/
I know its from CNN but im at work and in a hurry so I just posted the quickest link. basically they are saying now that what they have found isnt from the plane, I find it curious however because where did the fuel slick and wreckage come from then?
We may never know what happened the the Air France plane. If she lost control and lawn darted into the atlantic its possible that at those speeds whatever didnt disintegrate upon impact sank very rapidly.
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Some of the news stories about this latest development are really puzzling. I'm no fan of CNN but the link I posted they seem to be more concerned with speculation about the pitot tubes and what may have caused the crash than they are about this wreckage.
If what they found isnt from the Air France plane....they what plane is it from? They said it was fuel, a A/C seat and a 23ft piece of fusalage. Sooo is there another plane that has gone missing lately? This type of stuff doesnt ussually float around in that part of the Atlantic does it?
I hate to say this but, something smells fishy, I'm sure the conspiracy people will make alot of this new information and maybe they are right to do so.
It's very coincidental to find wreckage in the same area they are searching for the Air France plane just to discover that its not from THAT plane and THEN to not make much of the fact that it could be from a 2nd crashed airliner?
Weird
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If there was a second airliner wouldn't there be an airline missing a plane? A flight plan not closed?
The latest I read is that none of the debris was aircraft related, meaning they have not located a trace of the plane in 4 days. All news outlets are running stories before confirmation of facts leading to confusion. Hell they outright dismissed a bomb yesterday becuase of the oil slick that today apparently is not av gas. How they determined that I don't know so is this true?
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The 'piece of aircraft' may very well turn out to be just one of the thousands of pieces of random junk floating in the oceans.
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The sad part is that the ocean is so littered these days that they can't even tell where the plane crashed with all the junk floating around. They were showing a floating wooden packing crate as 'air france' part in the newspaper.
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The sad part is that the ocean is so littered these days that they can't even tell where the plane crashed with all the junk floating around. They were showing a floating wooden packing crate as 'air france' part in the newspaper.
even if the floating debris they spotted were part of that aircraft, i seriously doubt that it's still very close tro where the aircraft went down. i think the currents would've carried the stuff pretty far away by now.
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(http://img145.imageshack.us/img145/4026/af447verticalstabiliser.jpg)
Obviously there is still a lot of unknown information but no question that at some point the rudder assembly failed identically to the AA flight. It would be unfair/unwise to claim that this is the root cause but as far as i'm concerned the airbus concepts specific to the use and bonding of composites in flight control surfaces is flat out wrong...
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That is a heck of an assumption and nothing "obvious" at all. It could have come off after impact, during break-up in the air.
How can you tell this was an individual component failure? How do you know it did not exceed its design specifications and only then failed? I think the only one convinced of your argument is you.
You have not presented anything which would indicate that piece of debris failed, while in controlled flight.
That's like finding a flat tire after wreck, and saying it must have been the cause of the deaths in the accident. Nevermind the concrete bridge abuttment the vehicle actually hit, while traveling at high speed.
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(http://img145.imageshack.us/img145/4026/af447verticalstabiliser.jpg)
Obviously there is still a lot of unknown information but no question that at some point the rudder assembly failed identically to the AA flight. It would be unfair/unwise to claim that this is the root cause but as far as i'm concerned the airbus concepts specific to the use and bonding of composites in flight control surfaces is flat out wrong...
:huh How do you figure that? Do you see something in that pic that the rest of us are missing? Have some info the rest of us dont knwo about yet?
I agree with skuzzy there is absolutly NOTHING to indicate that the rudder failed much less that it was the same situation as the AA flight.
After reading the accident further on the AA flight the pilots improper use of the rudder contributed to the rudder failure aby going left then right several times at full deflection.
Regardless I dont want to start another debate in this thread on the AA rudder failure.
Any accident investigator worth his salt would not make ANY determination regarding the rudder from the Air France crash and IMNSHO you really shouldnt either. It seems like your trying to push an agenda by fabricating facts to support your hypothesis.
From the little bit of information we do have the rudder (whatever it was made of) was the least of their worries in a thunderstorm with conflicting speed indicators
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I guess no aircraft crash except the Airbus, and that all of those do so because of structural weakness.
:t
Sarcasm put aside, I spent some 8 hrs on the road (couple of days ago, - we went fishing) with a friend of mine who worked as a flight planner. That was world-wide. His words were that frequently the ground planners would send aircraft into impossible conditions. That would lead to lively re-routes and some big words between pilots and planners.
He guessed at this as being a classical example of killing yourself by flying where and when you shouldn't be. The ride doesn't matter in that case.
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Humble is really reaching this time. His avatar name is really ironic.
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Just read some news. Some Air France Pilots refusing to fly until they get some info on the crash.
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Humble is really reaching this time. His avatar name is really ironic.
Humble consistently has me rolling on the floor. The juxtaposition of his name and his behavior is too outrageous to not be intentional. He is the prime stereotype of the internet know-it-all who refuses to admit a lack of knowledge. I think it is all an elaborate joke. At least I hope it is. Not just this thread. There are many examples.
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As to the subject matter of the thread, as a pilot with 20+ years flying in all sorts of weather and some ocean crossing experience I think it was a bomb or a very rapidly progressing fire.
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Does anyone think it could be a "Austral Líneas Aéreas 2553" repeat?.
Is it possible that experienced pilots made the same mistake?
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As to the subject matter of the thread, as a pilot with 20+ years flying in all sorts of weather and some ocean crossing experience I think it was a bomb or a very rapidly progressing fire.
We were talking about this the other day, and based solely on the automated information received saying multiple main bus failures and loss of pressurization then silence, I'd have to agree. Either a massive structural failure caused by weather, or a bomb.
Based on the rumors of threats, I'd have to lean towards a bomb.
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newest development:
"Two names on doomed Air France Flight 447's passenger list also appear on a list of radical Muslims considered a threat to France, according to French investigators.
French secret servicemen established the connection while working through the list of those who boarded the doomed Airbus in Rio de Janeiro, Brazil, on May 31. Agents are now trying to establish dates of birth for the two dead passengers, and family connections.
There is a possibility that the name similarities are simply a "macabre coincidence," the source added, but the revelation is still being "taken very seriously." Soon after news of the fatal crash broke, agents working for the DGSE (Direction Générale de la Sécurité Extérieure), were dispatched to Brazil. It was there that they established that two names on the passenger list are also on highly classified documents listing the names of radical Muslims considered a threat to the French Republic.
A source working for the French security services told Paris weekly L’Express that the link was "highly significant."
France has received numerous threats from Islamic terrorist groups in recent months, especially since French troops were sent to fight in Afghanistan. Security chiefs have been particularly worried about airborne homicide attacks similar to Sept. 11."
:noid
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Its possible..... but don't Terrorist claim responsibility....... If someone or more go to this much trouble they generaly make it known that Hey look at me I did this....
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I have to agree with FireDrgn. If the accident were caused by a terrorist organization aiming to destroy that plane sometime in-flight over the ocean, that same organization would have claimed responsibility by now.
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In fact I'm surprised nobody did now that they brought the possibility to public.
It's like a free suicide bombing - get the credit without actually doing anything.
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In fact I'm surprised nobody did now that they brought the possibility to public.
It's like a free suicide bombing - get the credit without actually doing anything.
r perhaps, if it were one of these groups, possibly they've discovered, that it could be more effective to keep quiet, and let people worry more?
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"Final Destination" ya just can't cheat death.
http://www.foxnews.com/story/0,2933,525835,00.html
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What do you think of this?
The aircraft, which left from Posadas and was headed to Buenos Aires, was forced to divert towards Fray Bentos to avoid a storm. Examination of the aircraft's black box revealed that shortly after this diversion, the aircraft's airspeed began to fall to an alarmingly slow velocity. In response, the pilots repeatedly increased power to the turbines in order to maintain velocity. Seeing no improvement in the aircraft's airspeed, the pilots then contacted the control tower in Ezeiza Airport and requested clearance to descend to a lower altitude. After receiving no response, the pilots lowered the aircraft's wing slats to maintain their altitude and lower the plane's stall speed. When lowering the slats however, one of them was torn from the aircraft, causing catastrophic asymmetry in the air flow over the wings. The plane immediately became uncontrollable and crashed.
Austral Líneas Aéreas 2553, better known as Austral 2553 is the name of an Douglas DC-9 aircraft of Austral Líneas Aéreas, registered as LV-WEG [1] which crashed in Fray Bentos, Uruguay, on October 10, 1997. All 74 passengers and crew were killed on impact.
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forgive me for my lack of knowledge with aeroplanes and flights,
But if an airliner suffered engine failure would it be able to glide gentley down like other planes?
Yes, a 767 did it after the crew ran it out of fuel due to a 'minor miscalculation!' The "Gimli Glider" They heard a loud "BONG" from the computer which they never heard before and the engines quit. They went for the engines out checklist and found there was none since both engines shouldn't quit at the same time. The flight computer shut down since it was powered by the engines. They had about a 12:1 glide ratio which is pretty good and ended up landing on an old military runway which was converted to a racetrack unknown to the pilots. Nobody was injured in the landing. The successful landing was attributed to the pilot who was also a glider pilot.
(http://i703.photobucket.com/albums/ww35/strong1001/gimli_on_tarmac.jpg)
They sent out some mechanics to fix the nose gear(Who also ran out of gas getting there, lol) and it flew off the track 2 days later.
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What do you think of this?
The aircraft, which left from Posadas and was headed to Buenos Aires, was forced to divert towards Fray Bentos to avoid a storm. Examination of the aircraft's black box revealed that shortly after this diversion, the aircraft's airspeed began to fall to an alarmingly slow velocity. In response, the pilots repeatedly increased power to the turbines in order to maintain velocity. Seeing no improvement in the aircraft's airspeed, the pilots then contacted the control tower in Ezeiza Airport and requested clearance to descend to a lower altitude. After receiving no response, the pilots lowered the aircraft's wing slats to maintain their altitude and lower the plane's stall speed. When lowering the slats however, one of them was torn from the aircraft, causing catastrophic asymmetry in the air flow over the wings. The plane immediately became uncontrollable and crashed.
Austral Líneas Aéreas 2553, better known as Austral 2553 is the name of an Douglas DC-9 aircraft of Austral Líneas Aéreas, registered as LV-WEG [1] which crashed in Fray Bentos, Uruguay, on October 10, 1997. All 74 passengers and crew were killed on impact.
There has been several suspicions about the accident being caused by a faulty type of speed sensor that Air France is in process of replacing in the whole fleet due to freezing up in high-altitude and unconventional conditions (i.e. where they shouldn't normally freeze). The sensor was not replaced yet in the accident plane. Not all Airbuses are equiped with it - but this could certainlyl have been the outcome if the airspeed indicator froze.
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They have said the plane was flying too fast or too slow. They said also there was a problem regarding speed reading of instruments. Is it possible in an airbus to make a mistake due to wrong speed reading that damages the plane?
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They have said the plane was flying too fast or too slow. They said also there was a problem regarding speed reading of instruments. Is it possible in an airbus to make a mistake due to wrong speed reading that damages the plane?
If the flight computer is being fed with false information, the crew is in zero visibility enviroment in a thunder cloud and in middle of the sea.. The computer may have stalled or dived the plane with the crew being uncertain to what's happening. One false assumption may lead to overstressing the airframe and that's all it needs.
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If the flight computer is being fed with false information, the crew is in zero visibility enviroment in a thunder cloud and in middle of the sea.. The computer may have stalled or dived the plane with the crew being uncertain to what's happening. One false assumption may lead to overstressing the airframe and that's all it needs.
here's a question?
over land, all commercial flights like this are on radar all the time. is there radar that far out?
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What caused the wrongfull speed reading?
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another question - surely they have GPS for navigation and to double-check TAS. if GPS TAS doesnt match the instrument indicated TAS theres something wrong?
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Wouldn't the GPS give ground speed instead? The satellite doesn't know what the winds are does it?
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It's normal to speculate. And that is exactly what the thread is doing.
Otherwise...until there is definitive proof the guessing in this thread is akin to speculating how much dust the Big Bang created.
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What caused the wrongfull speed reading?
Nothing is certain but the plane reported weird readings and the sensor has a history of ice induced malfunctions. Shortly after that automatic system notices reported system malfunction after another (plane breaking up in air?).
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Wouldn't the GPS give ground speed instead? The satellite doesn't know what the winds are does it?
sry yes ground speed, presumably the instruments also give an indication of ground speed calculated from IAS?
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The failure of one air data system, air data computer or smartprobe (or whatever Airbus calls them) wouldn't bring down the airplane. On an airplane as sophisticated as the A330 you likely would have an air data miscompare message which very likely would disengage the autopilot leaving the standby systems (which are independent of the main ADCs) giving reliable information. The autopilot disengaging in that situation would leave the airplane flying in its previously trimmed condition and present no challenge to the flight crew to resume hand flying. They would also know it failed because they would have the aural autopilot disengage warning playing until they silenced it. If there is a miscompare I imagine the 330 would tell you which has failed but troubleshooting shouldn't prove to be a difficult task to determine the failed system.
Even with no airspeed information the airplane will still fly. Leaving the thrust levers where they were, keeping the pitch attitude where it needs to be to maintain level-ish flight and using your still working navigation systems would add workload but not present undue risk to those on board. We don't know anything about this accident and the facts we do have can present in several different ways. I'll keep waiting for more facts.
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here's a question?
over land, all commercial flights like this are on radar all the time. is there radar that far out?
They were beyond radar range. No radar contact.
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The failure of one air data system, air data computer or smartprobe (or whatever Airbus calls them) wouldn't bring down the airplane. On an airplane as sophisticated as the A330 you likely would have an air data miscompare message which very likely would disengage the autopilot leaving the standby systems (which are independent of the main ADCs) giving reliable information. The autopilot disengaging in that situation would leave the airplane flying in its previously trimmed condition and present no challenge to the flight crew to resume hand flying. They would also know it failed because they would have the aural autopilot disengage warning playing until they silenced it. If there is a miscompare I imagine the 330 would tell you which has failed but troubleshooting shouldn't prove to be a difficult task to determine the failed system.
Even with no airspeed information the airplane will still fly. Leaving the thrust levers where they were, keeping the pitch attitude where it needs to be to maintain level-ish flight and using your still working navigation systems would add workload but not present undue risk to those on board. We don't know anything about this accident and the facts we do have can present in several different ways. I'll keep waiting for more facts.
Probably the systems are more advanced nowadays but I remember seeing several cases in aircraft crash investigation series where false readings and no visibility caused the crew to rollercoast 10k up and down almost hitting the ground at lowest points. Aircraft was giving the crew two readings and they didn't know which to believe. Eventually they crashed just because they had no ground contact and misread the airspeed.
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Such would not be the case of the airplane in question. It's a very low time/low cycle airplane delivered in 2005.
I cannot imagine it being delivered without systems as I described. New off the line Embraers and even my 10 year old airplane have such systems in place. The data of all systems will be compared and if they exceed the tolerances you will receive a miscompare. Your options then become to switch to the good system, typically regaining control of the autopilot when doing so or if for some reason both main systems dropped offline at the same time (not even a 1x10^9 chance for that) you'll have standby instruments running on their own independent air sources which on a 330 are located left center of the instrument panel adjacent to the captain side PFD.
Even if a complete ADC failure were to occur where you flew through a giant film of jello clogging all of the air data probes the airplane wouldn't fall out of the sky. This would be losing ADC/ADS 1, ADC/ADS 2 and the Standby instruments (note: This doesn't happen) resulting in no airspeed/altitude indications. During cruise time the loss of airspeed and altitude indication would provide little more than an annoyance to a crew. Your navigation systems are still operating and prudence would dictate offsetting course as you will not know your exact altitude. You'll still have attitude control, control of the engines and surfaces and lots of time to find your way to good weather to make a landing in visual conditions. This would be greatly aided with an AoA (Angle of Attack) indication which are options (not standard) on Boeings and I would expect not standard on Airbus given their levels of electronic integration.
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even if its discovered to be a bomb, another reason will be generated to avoid panic as this economy can not stomach the thought