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Thrust Reversers Didn't Cause Crash  
User currently onlineBruce From United States of America, joined May 1999, 5059 posts, RR: 15
Posted (14 years 11 months 3 weeks 4 days 9 hours ago) and read 1269 times:

I am now convinced the thrust reversers on Egypt 990 did not cause its crash. If one reverser deploys, the plane will tend to spin (turn over). When this happens you will tend to be thrown off your straight-line course to whichever direction you turned over. Usually you can't recover.

New radar data indicates that the plane dropped very suddenly and fast, almost 700 miles per hour, from 33,000 to 16,000 feet in less than 30 seconds, at which point the crew recovered momentarily and climbed to 24,000. They then dropped again, and lost contact (probably broke up due to extreme stress on the airframe) at 10,000. Also significant it that all this time the plane continued to fly in a STRAIGHT LINE.

My theories are: a bomb and/or fire that did not breach the hull but rather severed hydraulic lines to the tail (elevator & stabilizer), or some other kind of mechanical failure that caused the elevator to tilt down (pointing the nose way down). The crew was not able to maintain altitude, but they did have direction control which would probably rule out a wing & flap problem or rudder problem.

Any other thoughts?


Bruce Leibowitz - Jackson, MS (KJAN) - Canon 50D/100-400L IS lens
9 replies: All unread, jump to last
 
User currently offlineDeltaAir From United States of America, joined May 1999, 1094 posts, RR: 0
Reply 1, posted (14 years 11 months 3 weeks 4 days 8 hours ago) and read 1169 times:

I agree with you as well. We also need to take into account the lack of communication from 990 to JFK. The 767 has built in safeguards to prevent total electrical failure, the RAM and APU. It is possible that the electrical lines were severed. Another thing is that a pilot of this experience would not have allowed the thrust reverser problem to go on without alerting JFK or attempting to recover. This may end up like TWA800 where we never will know what happened.

User currently onlineBruce From United States of America, joined May 1999, 5059 posts, RR: 15
Reply 2, posted (14 years 11 months 3 weeks 4 days 8 hours ago) and read 1159 times:

I do not believe that ALL electrical lines were cutoff. The transponders were working to relay radar data back to the ATC center. It wasn't a total failure until it broke up which I believe was caused by higher stresses than that airframe was tested to handle, or possibly it broke up when the fire breached the frame. I tend to believe the over-stressed theory because according to the radar hits, no plane except maybe a fighter jet can survive drops like that


Bruce Leibowitz - Jackson, MS (KJAN) - Canon 50D/100-400L IS lens
User currently onlineBruce From United States of America, joined May 1999, 5059 posts, RR: 15
Reply 3, posted (14 years 11 months 3 weeks 4 days 8 hours ago) and read 1154 times:

There were lobster fishermen about 7 miles away from the approx. point of impact and they reported hearing TWO very unusual "booms" but could see nothing in the black of night. This points to this direction: The plane wasn't fully engulfed in a ball of fire when it hit, because you'd see that kind of flame/explosion from miles away, and possibly TWO large sections hit the water, meaning an in-air breakup. This would lead me away from the bomb theory toward the mechanical failure theory, but at this point they're both possible


Bruce Leibowitz - Jackson, MS (KJAN) - Canon 50D/100-400L IS lens
User currently offlineMirage From Portugal, joined May 1999, 3125 posts, RR: 14
Reply 4, posted (14 years 11 months 3 weeks 4 days 7 hours ago) and read 1155 times:

There was no bomb.
If it was a bomb why nobody claimed the authority so far?


User currently onlineBruce From United States of America, joined May 1999, 5059 posts, RR: 15
Reply 5, posted (14 years 11 months 3 weeks 4 days 7 hours ago) and read 1150 times:

good point, Mirage. PLus, if it was a bomb, it probably would have broken the plane up at a higher altitude. Remember Pan Am in Lockerbie? I was thinking "bomb" because that could have caused loss of control to the tail section. But even a small amount would blow a hole in the fuselage.

This crew definitely had at least SOME power as well as control of the rudder and wings and full power to the engines.



Bruce Leibowitz - Jackson, MS (KJAN) - Canon 50D/100-400L IS lens
User currently offlineIainhol From , joined Dec 1969, posts, RR:
Reply 6, posted (14 years 11 months 3 weeks 4 days 7 hours ago) and read 1153 times:

I would like to say that you guys know nothing about the case of this airplane going down!!! You have not seen the crash site and heard all there is to be said, and what you have heard some news person might be saying and not valid. You guys really should not speculate until we know what happend and then talk. Think of all those people who lost some one in this crash and they have not found whole bodies so you will be lucky to burry an arm!
Iain


User currently offlineAC183 From Canada, joined Jul 1999, 1532 posts, RR: 2
Reply 7, posted (14 years 11 months 3 weeks 4 days 7 hours ago) and read 1142 times:

I think its way too early to draw any conclusions about the crash. While it would seem the descent rate indicates a powered dive, the investigation will have to determine this for themselves. And there is nothing saying the crew ever regained any control or consciousness. For all we know, that was the autopilot system that caused any changes. But it may not have been. We don't know.

User currently offlineSp-deluxe From , joined Dec 1969, posts, RR:
Reply 8, posted (14 years 11 months 3 weeks 4 days 6 hours ago) and read 1134 times:

everyone seems to be focusing on one engine going into reverse, could both have done so, would this put the engine into a straigh dive like what happened. If one engine was in reverse would a captain put the other in reverse to counter the balance problem.



User currently offlineAmerican 767 From United States of America, joined May 1999, 3872 posts, RR: 12
Reply 9, posted (14 years 11 months 3 weeks 4 days 5 hours ago) and read 1135 times:
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I maintain the fact that there has been a problem with the thrust reversers on PW powered Boeing 767's but having just read that the aircraft plunged from FL330 to 19000ft then climbed up to FL240 before falling down to 10000ft, yes like a roller coaster, I would put aside the theory of thrust reversers.

Well, we have no clue. We still don't know what happened, the black boxes have not been analysed yet. We cannot say that the thrust reverser was the only cause of the crash. It is possible that BOTH of them had come out during the last minute of the flight, but I know that not just one of them would have been the cause of the disaster although the pilots were complaining of a thrust reverser problem on one engine of their 767. That particular aircraft did have its thrust reversers modified after the Lauda disaster. If that was really the problem, the FAA would have grounded all PW powered 767's until each one of them would be recertified to fly in airworthy conditions.
Because if it did happen on only one engine, like on Lauda Air, the aircraft would have spinned in either direction depending on which engine would have had the thrust reverser problem. And it did not happen with Egypt Air, the aicraft continue flying straight on course while suddenly loosing a lot of altitude. I would eliminate the idea of bomb threat. I would also elimitate the power loss of both engines because if the 767 looses all of its power at 33000ft, it can glide more than 100 nautical miles. I wouldn't put everything on hydraulic failures because the aircraft still had some of the control surfaces working properly, although it is possible that hydraulic lines controlling the elevator on the tail were severely damaged. Well the 767 never had hydraulics problems like the DC-10 had, but...it can always happen on just one flight no matter what aircraft it is. The other thing that is possible is that the autopilot system went down, thus loosing the ability of maintaining the altitude constant.

The Boeing 767 is an excellent aicraft with a good safety record in its almost twenty years of airline operation. It is one of the most efficient airliners in the industry, ETOPS (a certification applicable to twinjets for overwater flights) started with it and it is the aircaft flown the most on trasatlantic fligths. Boeing will continue building it for many more years to come.

Ben Soriano
Brussels Belgium



Ben Soriano
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