Air France Jet Missing Off Brazil Coast

[Denholm]

Wow, that would be hilarious.

I think if it were a terrorist attack the party responsible would have taken responsibility (fame and glory).

[MrRiplEy[H]]

Wow, that would be hilarious.

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.

[Denholm]

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.

[MrRiplEy[H]]

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..

[Denholm]

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.

[Fishu]

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.

[-tronski-]

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

[humble]

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.

[RTHolmes]

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 ...

[humble]

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.

[humble]

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.

[MrRiplEy[H]]

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?

[humble]

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.

[ghostdancer]

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.

[Skuzzy]

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.