Aces High Bulletin Board
General Forums => The O' Club => Topic started by: Chortle on October 26, 2004, 01:33:11 PM
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Only heard a brief piece of this news item but it appears the co-pilot was too aggressive with the rudder and snapped the tail off? That cant be right can it?
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poor simulator training and a rudder response that was too powerful for use at higher airspeeds joined up with wake turbulance to cause a catostrophe.
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Rather than too strong a rudder force, I believer it was too weak a tail structure, or at the very least, a poor design of the relationship between rudder force tail structure. This was an engineering failure.
Structural failure on take off is generally not pilot error.
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I thought the plane had just taken off, therefore was flying pretty slow?
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i think airbuss's have lost vertical stablizers before, the tails are composit construction with metal mounting plates laminated into the base.
the plates delaminate and the vertical stablizer falls off under extreme rudder use.
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If HT modeled AH differently you would see just how easy it is to snap a rudder at speed.
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It had. Apparently the guy didnt realize the huge stress he was putting on the tail by constantly operating the rudder like that.
http://aolsvc.news.aol.com/news/article.adp?id=20041026072609990001
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link to the investigation findings: http://www.airdisaster.com/news/1004/26/news.shtml
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what I gathered was that on climb out the airplane encountered wake turbulance and the co-pilot (who was at the controls) over reacted using rudder which broke the rudder empenage from the fuselage. There were two underlying themes noted in the write up which I read. First, the co-pilot had received insufficient or incorrect flight simulator training at the airline and second, that the aircraft rudder system allowed more force to be used than was safe at the speed the airplane was traveling at when the failure ocurred.
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The accident occured during climbout with the A-300 accelerating through 260 knots.
The vertical stabilizer clearly should have been designed to take the loads of whatever rudder deflection is available to the pilot at that speed. If it was, then there was a structural weakness that caused the failure. I simply don't buy that the co-pilot pushed to hard on the rudder pedal.
MiG
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Friends don't let friends fly Airbus
If it ain't Boeing, I ain't going
The rudder should not break due to the pilot pushing the rudder pedals, period.
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Most folks don't realize the highly sensitive nature of this airplane's rudder system. I think 3 inches and not very much force is all that is required for full deflection of the rudder pedals. Here's a snippit from an email I wrote to a friend this morning after hearing the released findings.
Hope all is well in the land of CT today. Im a little disappointed because they blamed the Co-Pilot of AAL 587. (just saw the headline, but I've been following the crash investigation).
The Airbus A-300 only requires about 3 inches of pedal movement for full deflection, and there is very little resistance. If you get into turbulence (wake turbulence from a 747 variety) you get a bit of pucker factor. I know that my legs tense up at the first sign of an emergency (only for a moment while my brain starts to process again) and if that happened or he was just knocked around, kicking full rudder in that airplane is no chore. I hope Airbus gets *****-slapped with a lawsuit that puts them under because I don't think its AAL's fault in the least. Especailly the co-pilot. They followed a training program approved by Airbus and there were some rudder things specifically brought up during the course of the investigation that Airbus had signed off on.
Yet another reason "if it ain't Boeing, I ain't going."
Have a good'n
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I agree 100%. In a fly by wire system if the pilot can damage the flight controls by pushing too hard on the rudder pedals then the problem is with the plane and the fly by wire system. It is easy to limit the travel of the rudder to safe deflections at different speeds. Allowing deflections where the rudder snaps off is criminal.
So easy to blame the pilot. This is one instance where a good old American lawsuit is totally justified.
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that is ahorrible you cnat do a full rudder ..at those speeds?
wow..I have no hope..
i routinly crab all the way in the cessna..I find my self doing it too much ..I think AH gives me bad habits..I seem to fly the c152 a bit agressive soemtimes..
I mean how many tiems do you coem in complty sideways to burn off speed when landing in AH?..lololo
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If it ain't Boeing, I ain't going.
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Sounds a lot like a problem in the "control laws". Basically, there's a computer program the limits the fly-by-wire inputs throughtout the flight envelope.
Airbus has had "control law" issues before (and IIRC) they always finger the pilots first, claiming the programming is flawless. So that part is no suprise.
I can tell you a story of the dark and stormy night I was F/E on a functional check flight on a 727 after phase maintenance. This all happened so fast that it takes way longer to read it than it did to happen. It happened so fast, we were all pretty much stunned into inaction.
The Captain was an ex-Navy guy with a reputation for being a bit agressive. One of the checks was to turn off both yaw dampers, induce mild dutch roll (10-20 degree oscillation) and then turn on one yaw damper. The yaw damper should/did immediately stop the dutch roll. Repeat test for other yaw damper.
Well, F/O flew the first dutch roll (all you had to do to induce it was turn off the yaw dampers and push in some rudder and quickly release it. It would start dutch rolling with ever increasing amplitude. You just turned on the yaw damper when it was banking back an forth at about 20 degrees) and the Captain decided the F/O hadn't REALLY given it a good dutch roll.
So, the Captain does the next one. He pretty much pegs the rudder to the floor for a hearty second or so, which gets us rolling up to about 30 degrees or so and then he releases it all at once and lets the amplitude increase up to about 60-70 degrees in a heartbeat.
The cockpit is vewy, vewy, quiet. I'm hanging on to the F/O Desk, the maintenance guys are grabbing anything bolted to the floor.. and then the Captain reaches to slap on the yaw damper at about 70 degrees of bank and swinging for more. The maintenance chief yells "NO!"
WHAM! The yaw damper rolls us out right now.
The maintenance chief then debriefs the Captain for an extremely long time and in great detail about how the vert stab is attached to the aircraft and just what sort of stresses it can and cannot take. He describes in great detail just exactly how much he figures the T-tail got twisted and how he expects to have to do a two-day inspection on the airplane now.
We actually finished the rest of the check and rtb'd safely. They did re-check the vert stab but it was apparently OK.
I was always watching pretty close and spoke up readily when I flew with that guy after that though.
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Difference is... Boeing designed an airplane that would stay in one piece if the pilot or control system fubared. Airbus didn't.
Boeing, going, etc.
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Hey.. they would have had to add 150 pounds of vertical empennage support to that 375,000 takeoff weight airplane!
Think of the loss in fuel economy!!
Interesting discussion of the accident from a "pilot defense" point of view.
Here (http://www.iasa-intl.com/folders/AA587revisited/NTSB-FAA%20Final%20Copy.doc)
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Interesting and alarming stuff. Thanks for the pilot defense link Toad - Airbus claiming that certification data is 'no longer available' is suspect.
For a layman, designing an airliner that can effectively break itself apart without 'proper' pilot training, just by using it's control surfaces sounds like they did a crappy job.
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If a Control Member can't take the force a Pilot can apply then something needs to be done to limit that force. I really don't want to be flying in an aircraft that self-destructs from what appear to be normal control inputs.
I wonder if anyone is still flying an Airbus with their feet on the rudders? (Bad joke...)
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Originally posted by Otto
If a Control Member can't take the force a Pilot can apply then something needs to be done to limit that force. I really don't want to be flying in an aircraft that self-destructs from what appear to be normal control inputs.
what he said
if that's the best they can do, I am inclined not to rule out an onboard bomb
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pilots died, therefore its pilot error.
Poor guys cant defend themselves so the studmuffins pin the blame on them.
Plenty of crashes are pilot error, this isnt one of um.