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Old 1st September 2005 | 15:52
  #25 (permalink)  
AirRabbit
 
Joined: Apr 2005
Posts: 801
Likes: 1
From: Southeast USA
CaptainSandL:

“Witnesses estimated that both engines were operated in reverse for a period of 30 to 90 seconds. During this time, several Air Florida and American Airlines personnel observed snow and/or slush being blown toward the front of the aircraft.”

It then goes on to give various other eyewitness reports of whether snow was seen or not on the wings after pushback.
Either way, my point was that the use of reverse thrust before departure in contaminated/icing conditions is a bad move.
I wasn't disagreeing with the point you were making and I'm quite familiar with the accident report. Until this accident, I was a very strong believer in the non-biased approach of accident investigation organizations, particularly when they are governmental agencies; and I continue to have zero problems with finding the facts behind an accident or incident -- regardless of what they might be.

Unfortunately, the report of this particular accident doesn't tell all the facts and it reaches conclusions (leading to statements of "probable cause" and "contributing causes") which are not accurate. In fact, in some cases, the contridictions to the conclusions are part of the "factual report;" they're just ignored.

The cause of the accident was the leading edge of the wings being contaminated with clear, hard ice, and were, therefore, deformed to the extent that only the inboard portion of the wing generated lift at the airspeeds where the crew was preparing the airplane to fly (just prior to rotation). The outboard portion of the wings would not generate lift with that deformation until achieving airspeeds well beyond where the airplane became airborne. This asymmetry in lift (inboard = forward and outboard = aft) caused the airplane to "rotate" itself (beyond the control capability of the crew) and achieved a pitch of approximately 22 to 24 degrees nose up, from which the crew was unable to recover. The ice on the wing leading edges did not come from the inclement weather (other than the temperature); it came from the improper de-icing process during which the airplane was "de-iced" with 160 degree water and a 3% glycol solution.

I am pleased that the information generated from this accident has caused ground crew and flight crew alike to be more aware of de-icing procedures, hold-over times, etc. But when someone comments about the "facts" of the accident and innocently believes the "factual report," I try to set the record straight. A daunting task, but one that I believe in.
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