B737 - self reversing from stand
Joined: May 2003
Posts: 663
Likes: 0
From: Stockport
Remember being at Minneapolis and powering back on a B727, funny watching a DC-9 get it wrong and have to taxi forward again onto stand and have another go getting the right direction
Northwest seemed to do it all the time as
in an hours or so saw quite a large number
G-I-B
Northwest seemed to do it all the time as
in an hours or so saw quite a large number
G-I-B
Joined: Nov 2003
Posts: 496
Likes: 12
From: UK
AirRabbit
I stand corrected it was not a true self manouvered power back.
Nevertheless the accident report states on page 3 re the first failed pushback:
“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.
S & L
I stand corrected it was not a true self manouvered power back.
Nevertheless the accident report states on page 3 re the first failed pushback:
“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.
S & L
Last edited by CaptainSandL; 31st August 2005 at 09:01.
Paxing All Over The World
Joined: May 2001
Posts: 10,841
Likes: 328
From: Hertfordshire, UK.
It seems that the high engined a/c can do this with greater safety.
My nephew used to drive Jetstream 41s (not in UK) and they did powerbacks all the time. He said, Change pitch and brakes off. Crack the throttle and as soon as she breaks out, close it again. If needs be, give another blip. When she has stopped, change pitch and apply brakes.
My nephew used to drive Jetstream 41s (not in UK) and they did powerbacks all the time. He said, Change pitch and brakes off. Crack the throttle and as soon as she breaks out, close it again. If needs be, give another blip. When she has stopped, change pitch and apply brakes.
Joined: Apr 2005
Posts: 801
Likes: 1
From: Southeast USA
CaptainSandL:
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.
“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.
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.
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.
