NTSB: Mechanical and pilot errors cited in American overrun

derg

derg

Apparently a "terse" writer
Staff member
NTSB: Mechanical and pilot errors cited in American overrun


The US National Transportation Safety Board (NTSB) has found that a combination of mechanical defects and the captain's failure to monitor the speed brakes resulted in a runway overrun of an American Airlines Boeing 757-200 in Jackson Hole, Wyoming, in December 2010.

The aircraft stopped 222m (730ft) beyond the threshold of the 6,500ft runway in deep snow after the brakes and thrust reversers failed to deploy. None of the 185 passengers and crew onboard were injured.



The overrun was caused by the confluence of two separate mechanical issues and the captain's failure to follow company procedure to confirm that the brakes had deployed and then manually deploy them when they had not, according to the NTSB report that was released on 5 June.

The brakes did not deploy due to an assembly defect in their no-back clutch mechanism while the thrust reversers were prevented from deploying by a rare mechanical and hydraulic interaction that occurred at the moment when the first officer attempted to deploy them.

The captain, who was the monitoring pilot during landing, mistakenly stated that the brakes had deployed without observing whether they had actually deployed. He then took the controls from the first officer when the thrust reversers failed and managed to deploy them after 18 seconds.

The NTSB found that if the captain had manually deployed the brakes the aircraft could have stopped about 4,500ft down the runway without the thrust reversers.

The board recommends that air carriers include training of situations where the brakes do not deploy for pilots, new air transport aircraft include an unique aural alert when the brakes do not deploy, and Boeing provides guidance to pilots when an unintended thrust reverser lockout occurs, based on the results of its investigation.

American did not comment on the findings.
Click to expand...
 
Skåning said:
So the auto brakes didnt work and nobody pushed the pedals?
Click to expand...

In the first paragraph, they mentioned the speed brakes and then just said brakes after that. I think they were referring to the speed brakes.
 
It's a poorly written article.

They were talking about ground spoilers, but referred to them as speed brakes (technically close), but then transitioned to talking about brakes.

It got me the first two reads.
 
Derg said:
It's a poorly written article.

They were talking about ground spoilers, but referred to them as speed brakes (technically close), but then transitioned to talking about brakes.

It got me the first two reads.
Click to expand...

Maybe it was more of a description than a technical term ;)
 
Well considering they had two important items fail and the airport conditions with no body hurt I think the pilots did an excellent job! It was a crappy day there WX wise
 
JayAre said:
Well considering they had two important items fail and the airport conditions with no body hurt I think the pilots did an excellent job! It was a crappy day there WX wise
Click to expand...

It seems like the NTSB agenda is to always blame the pilots. I'm sure the NTSB could find a way to cite pilot error in an accident resulting from say, a bomb going off in flight.

"The NTSB has determined that the cause of this accident was catastrophic airframe failure, and subsequent in flight break-up as a result of an explosive device being detonated during cruise flight. A contributing factor to this accident was the failure of the flight crew to adequately detect and disarm the explosive device, and to attempt to hold the disintigrating airplane together with duct tape."
 
FWIW, Boeing procedure is to visually check the speedbrake handle actuates upon touchdown. That's the only indication they've deployed. If they didn't auto-deploy, you have to do it manually. Auto-speedbrake issues aside, the crew is responsible for making sure they've come out properly.
 
Derg said:
Well, if you forward slip it, the entire jet is a 'brake', am I right, am I right? ;)
Click to expand...

I was in the back once when an SWA crew actually put us in a forward slip on a high approach. I asked them about it on the way out the door. Capt and FO both grinned and started giggling. It was hilarious.
 
inigo88 said:
I was in the back once when an SWA crew actually put us in a forward slip on a high approach. I asked them about it on the way out the door. Capt and FO both grinned and started giggling. It was hilarious.
Click to expand...
"Here... hold my coffee... watch this!"
 
dasleben said:
FWIW, Boeing procedure is to visually check the speedbrake handle actuates upon touchdown. That's the only indication they've deployed. If they didn't auto-deploy, you have to do it manually. Auto-speedbrake issues aside, the crew is responsible for making sure they've come out properly.
Click to expand...
The "I forgot" circuit on the 757/767 will also deploy the speedbrakes when the thrust reversers are deployed, no?
inigo88 said:
I was in the back once when an SWA crew actually put us in a forward slip on a high approach. I asked them about it on the way out the door. Capt and FO both grinned and started giggling. It was hilarious.
Click to expand...
Obligatory.
 
Autothrust Blue said:
The "I forgot" circuit on the 757/767 will also deploy the speedbrakes when the thrust reversers are deployed, no?
Click to expand...

Yeah, that's what's supposed to happen. That said, I've seen it do some funny things before. You really have to get in the habit of looking down there on every landing, particularly when braking action is a concern. It's easy to miss from either seat though, especially if you hear it slot back a bit, then it stows itself again (happens).
 
I wonder if AMR has the "Engine 1(2) Not in Reverse" "No Speedbrakes" calls like in another Boeing product.

Also, is the speedbrake deployment mechanically linked to the TR levers?
 
Apophis said:
It seems like the NTSB agenda is to always blame the pilots. I'm sure the NTSB could find a way to cite pilot error in an accident resulting from say, a bomb going off in flight.
Click to expand...

Maybe, but in this case it was really pilot error. On landing, pretty much the only thing the pilot not flying has to do (besides making sure the other guy keeps it on the runway) is confirm the spoilers/TRs deploy and give some sort of decreasing speed calls. Sure there were huge mitigating circumstances that caused this issue (double mechanical failure) but when you have a profile/call out that you do on EVERY landing (so it wasn't even some random immediate action item you only do in the once every six months), and you manage to mess it up, that is going to be called pilot error every time.

Now, in his defense, I've had the ground life dumping system fail on the CRJ several times before. Our actual procedure is to throw a little switch (that can be a pain to reach) to Manual Arm. If that doesn't work then you deploy the actual spoiler handle. We are so conditioned to saying "spoilers... two (TRs) in reverse, that when it DOESN'T happen it can be a bit of a shock and can take a few seconds (not 18 though) to realize what you are saying isn't matching up with what you are seeing and start throwing switches and levers.
 
dasleben said:
Yeah, that's what's supposed to happen. That said, I've seen it do some funny things before. You really have to get in the habit of looking down there on every landing, particularly when braking action is a concern. It's easy to miss from either seat though, especially if you hear it slot back a bit, then it stows itself again (happens).
Click to expand...
Having watched the "SPOILERS" indication go from CLOSED to OPEN then back to CLOSED then OPEN again on the -135/-145, I'll buy that. Air ground sensing is black magic...
 
Polar742 said:
I wonder if AMR has the "Engine 1(2) Not in Reverse" "No Speedbrakes" calls like in another Boeing product.

Also, is the speedbrake deployment mechanically linked to the TR levers?
Click to expand...

Isn't it main wheel spin-up and alternately TR deployment?
 
You must log in or register to reply here.
Back
Top