About the AA flight that crashed in Queens last year?

[Guest]

HiI am a little confused. I jsut saw on CNN a headline about the AA flight that crashed in Queens, NY last year. They said that they are looking into the role of the co-pilot because he had 'a history of over-reacting to wake turbulenc'. What does that mean? over-reaction to wake turbulence.... I know that CNN is alwasy trying to twist things and make stories how they preffer so there is probably something I don't get. Could the co-pilot have torn the plane apart and not the turbulence? I find that hard to believe.Any comments?Take careMike

[Guest mikehaska]

The thinking at the time was that American Airlines trained the pilots to aggressivly use rudder in the case of upset attitude conditions, specifically those induced by wake turbulence. It was thought that at the time, the pilots used too much rudder when they hit the wake turbulence, and that in conjunction with G forces, caused the rudder to separate. Had the pilot not used to much rudder, it would not have strained so hard against the g forces, and it would have remained intact.However, there is some question to if the plane's rudder, which was made of composites, failed, and that it was not caused by pilot action. This is bolstered by the fact that the plane was knocked on to it's tail while it was being built in France. Perhaps that caused damage which permanenantly damaged the plane.In any case, you are correct. A pilot should not be able to damage his plane by applying rudder- it simply had to be a combination of more factors than that (including the g-forces). I recall an accident where a Pacific Western 737-200, landing at at Crambrook airfield in western Canada, encountered a runway plow on the runway while landing. They didn't see it due to bad visibility. In trying to avoid it, both pilots broke their legs stomping on the rudder so hard. Rudders should, and can, take a lot.

[Guest]

Thanks for the clarification. SO what they mean is that the co-pilot could have applied too much rudder, but what is the procedure for encountering wake? Why use rudder? shouln't you use ailerons, elevators, rudder to keep contol and get out..or would taht put too much stress on the ailerons and elevators?..I don't know, i'm not a real pilot so it's just my guess. Was for the 737...geeze..pilots broke their legs stepping on the rudder? hat must have been some strong reactions adn reflexes from them to hit so hard. Did they hit the plough in the end? Take careMike

[Guest]

Mike,When the FDR data was analysed after the crash, the data implied that there had been rapid reversing movements of the rudder and rudder pedals. What is not known was if it was one of the pilot making control inputs or a malfunction of one of the rudder control components that caused this rapid reversal. The general consensus of opinion is pointing at a control component failure, as the movements appear too rapid for a human to make.It was also found out that transport aircraft are NOT, nor are required to be, certified to withstand rapid rudder reversals. At work we had a notice from a aircraft manufacturer who had conducted tests on their aircraft types, and they stated that there was a very strong possibility that the vertical fin would also fail under these conditions. Take a look at the NTSB website for more info on the accident, especially the Recommendation Letter.http://www.ntsb.gov/events/2001/AA587/default.htmAs for the media, well they are not known for reporting the full facts when it comes to aviation accidents/incidents.

[Guest mikehaska]

Aviation Week just had a good article about what to do in the case of wake turbulence and such... it was very long and detailed. Essentially, it takes a lot of training and experience, it's not something that can simply be told.As for the PacWest crash, it didn't turn out so good. You can read the particulars here: http://www.airdisaster.com/cgi_bin/view_de...estern+AirlinesEssentially, they ran off the runway avoiding it, but they still crashed. The three "golden" factors that caused the crash were 1. Poor weather, causing bad visibility meant they didn't see the plow untill it was too late, 2. The plow operator was on the runway when the 737 was cleared to land, and 3. Thrust reverser problem meant that they couldn't go around in time.I find it fascinating how there are always at least three factors to a crash- if you removed any of those, the crash wouldn't have occured. This three rules theory works for almost all crashes.

[brucek 38]

Hi Mike,With a high angle of attack and slow speed, as in just after take-off, it's possible that the effect of the wake turbulance may have brought the aircraft close to a stall. For GA aircraft, and I assume heavies too, the rudder is the most effective control surface available to the pilot at slow speeds (due largely to the area of the control surface and the leverage it has from the center of lift). At a near-stall condition, excessive use of aelerons can be all that's required to stall the down-aeleron wing, due to the higher induced drag on that wing.That said, it's very hard to second-guess the reactions of the crew, especially with the unpredictability of something like wake turbulence. "Pilot Error" becomes so easy to blame when they aren't here to defend themselves.Bruce.

[Guest]

Wow! thanks for all the info guys. It certainly makes a lot more sense then what the media says. Take careMike

[Guest]

I tried to post this yesterday, but my connection failed. I'll try again.*****************The pilot induced rudder failure is a weak theory at best. Lets face it:103 seconds, rotation to impactRudder falls off first.Engines second, 10's of seconds of seconds later.Large vibrations heard in CVR. Why would ANY aircraft break up so violently, so quickly, so completely?The answers are not clear, but in any fashion...human intervention or fate...there is a serious problem when something like this happens without explanation.bt

[John_Cillis 2,406]

"there is a serious problem when something like this happens without explanation."I feel you need to rephrase that to say:"there is a serious problem when something like this happens without an explanation I accept."The first statement offers something as factual, when in fact some feel the explanation provided to this point is on the right track. What do I feel? I feel you have an aircraft which went through severe in flight turbulence in a prior flight, and was not thoroughly analyzed after the fact. I don't believe that an aircraft should have this happen, but you could have had an airframe stressed in a prior incident, including engine mounts and all the other points of failure. Had this aircraft been the victim of sabotage, which is a thought I know some worry about, I'd expect that anyone trying such a stunt would have targeted a flight with more P.R. value for those abroad who love watching people cry terrorism whenever an aircraft goes down. Targeting a flight full of nationals from a country not at war or in dispute with anyone isn't going to help a "cause". And part of the victory of terrorism is our fearing that everything is a terrorist incident. I'd say that is certainly valid in the post 9/11, and even pre 9/11 environment. Just as a bomb or bullet fired by a terrorist can hurt, so can the bullet of fear and skepticism that is part of their weaponry. It can be so strong, as to pull us away from the truth, and can cause more lives lost.Anyway, just my opinion, and in no way a thought that you shouldn't offer yours. Some skepticism is valuable, and in the cases of these tragic events, it can save future lives--especially if you are proven right. I guess you can say I'm just a skeptic of aircraft integrity, and our technology to detect the lack of it.Regards,John

[Guest mikehaska]

Well put, John. I think some people need to be reaquainted with a little idea called Occham's Razor: The simplest explaination is often correct. If we start jumping to assumptions and far out ideas, we might miss the answer right in front of our nose.

[Guest]

John, as always I must agree with your posts, for they are factual and fair-minded. That truth though, does not dismiss or eradicate the truths of mine.All I stated was there is no resolution to the tale as of yet.Official theories are just that, theory.I think I clearly stated, "human intervention or fate..."Skepticism is always good. Is that not what we both offer, except from two sides of the coin?Cheers,bt