twa747100
Posts: 549
Joined: Thu May 20, 1999 7:16 am

Thrust Reversers Cause Of 990?

Wed Nov 03, 1999 9:23 am

They say that the cause of 990 is the thrust reversers on the engines
~ This cant be true its physically impossible for them to open in mid air
Why? There is a sensor in truck that when pressed then and then only can the reversers open up.
~ If this is true its a big booboo for Boeing!
Well, what do you all think?
Matt
 
DeltaAir
Posts: 1059
Joined: Tue May 18, 1999 4:41 am

RE: Thrust Reversers Cause Of 990?

Wed Nov 03, 1999 9:41 am

The problem was suposedly corrected right after the Lauda accident. If it was a thrust reverser problem wouldn't be an equally important part of the engine manufactuer.
 
mirage
Posts: 3612
Joined: Mon May 31, 1999 4:44 am

RE: Thrust Reversers Cause Of 990?

Wed Nov 03, 1999 9:45 am

"They say that the cause of 990 is the thrust reversers on the engines"

They who???
 
OPNLguy
Posts: 11191
Joined: Tue Jun 15, 1999 11:29 am

RE: Thrust Reversers Cause Of 990?

Wed Nov 03, 1999 9:51 am

Don't know who "they" are, but that's just one possibility I'm sure will be considered.

As far as it being "impossible" for the reversers to deploy in-flight, yeah, they're not *supposed* to, but Murphy's Law and the Lauda crash show that it can indeed occur, even with the air/ground safety logic. In fact, check out this link for the Lauda report:

http://www.rvs.uni-bielefeld.de/~ladkin/Incidents/LaudaAir/LaudaRPT.html

They mention 3 different possible scenarios that caused the reverser to deploy, and were unable to determine which one caused the crash. According to one of the appendices, it appears that the main problem was with Pratt 4000-series engines, and not so much the JT9D, RB211, and CF6 engines on the 767 fleet.

Interesting reading.....
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
Guest

CNN Is Running With This Story

Wed Nov 03, 1999 9:56 am

CNN websites says under the developing stories section that one of the crew members on the Egypt air flight reported having trouble with the thrust reversers hours before the accident.

AND to twa747-100 i think the crash of a Lauda 767-300 when one of the reverse thrusters deployed midflight suggests that is possible!!

In that accident the pilots could have only possibly pulled out of the catastrophic deployment within 6 seconds of deployment.

What happens when one engine (only) deploys its reverse thust the one wing wants to go up and the other wing down.

However in the Lauda incident there was extensive fuselage breakup inflight, because of the immense stresses on the aircraft, did this happen on egyptair
 
Navion
Posts: 1052
Joined: Tue May 18, 1999 1:52 am

It Is A Possibility

Wed Nov 03, 1999 9:57 am

I'm afraid the characteristics of this crash could be consistent with an uncommanded thrust reverser deployment. I sure hope that didn't happen, especially since Boeing put a lot of effort into designing a supposedly foolproof fix. I sure hope that is not what happened. This is pretty serious business. By the way, if the Egyptair pilots who flew the aircraft to New York sensed a problem with the thrust reversers, then why would the aircraft continue on?
 
hmmmm...
Posts: 1959
Joined: Tue May 18, 1999 8:32 am

Fuse Pins

Wed Nov 03, 1999 11:05 am

It was my understanding that commercial airliners have fuse pins in the engine mounting pylons. The logic was that, in the event that an engine starts developing a mind of its own, it would shear the pin and fall away, hopefully saving the wing and everything else. Does the 767 not have fuse pins?
An optimist robs himself of the joy of being pleasantly surprised
 
OPNLguy
Posts: 11191
Joined: Tue Jun 15, 1999 11:29 am

RE: Fuse Pins

Wed Nov 03, 1999 11:40 am

IMHO (and I'm not an engineer) the fuse pins have certain uses, but they can't mitigate the effect of just *any* engine problem.

For example, if the aircraft had to make a full gear-up landing, the fuse pins would allow the engines to detach rather cleanly during the landing sequence with a better probability of not compromising the wing fuel tanks.

The big problem with a reverser deployment inflight is the immediate adverse aerodynamic effect it can have. For example, if you're running the lake in your speedboat and stick a canoe paddle in the water (wide face foward) on one side of the boat, you're going to start turning to that side in a hurry.

For a discussion of this as it affects the Lauda crash, see the report at:

http://www.rvs.uni-bielefeld.de/~ladkin/Incidents/LaudaAir/LaudaRPT.html

ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
Danny
Posts: 3714
Joined: Thu Apr 25, 2002 3:44 am

RE: CNN Is Running With This Story

Wed Nov 03, 1999 5:28 pm

In fact - the Egyptair is said to have broken up in midair. A radar observation said that it looked like an explosion. There are so many similarities to the Lauda crash. The sudden loss of altitude, break up, and not to forget - both aircraft used the same type of engines, the PW4060.
And I also heard that not ALL the engines were fixed...
 
Guest

RE: Thrust Reversers Cause Of 990?

Wed Nov 03, 1999 5:46 pm

how about we wait till we havea little more information before we go and make all these assumptions  

Who is online