AA 757 off runway excursion at JACKSON, Wyo

[MCM]

Also odd is the fact we do not see any spoilers deploy once the reversers are extended - something that should be automatic even with the spoilers in the down position.

Unless the spoilers on the 757 are inboard of the visible area on the video.

[aardvark2zz]

Originally Posted by Curtis Malone

If you don't mind my asking, how were you able to plot that data from that fairly poor-quality video?

- I mind
- From my experience this is a very good video.
- Just slow it down & you'll clearly see the 1000' distance markers; except for the 6000' one.

The reversers finally begin deploying at 4000 ft and are fully open by 5000 ft but begin to achieve thrust at 5500 ft, but by then the speed is near 80 knots.

Wow, from the long SWA1248 report (mods mine) :

o- ... using SWA routine/planned deceleration procedures to decelerate, showed that the airplane would likely have stopped about 1,351 feet beyond the end of the runway....

o- Under the same conditions and if the pilots had used Boeing’s reverse thrust procedures (...), simulations showed that the airplane would likely have stopped about 531 feet beyond the end of the runway.

o- However, simulations in which maximum reverse thrust was selected 2 seconds after touchdown and maintained until the airplane came to a complete stop (...) showed that the airplane could have stopped about 271 feet before the departure end of the runway.

Read the report at (hope correct)
http://www.ntsb.gov/publictn/2007/AAR0706.pdf

This report is one of the most convolutely badly written documents I have ever read.
It could be much simplified !!!
.

[Evan]

Originally Posted by MCM

Also odd is the fact we do not see any spoilers deploy once the reversers are extended - something that should be automatic even with the spoilers in the down position.

Unless the spoilers on the 757 are inboard of the visible area on the video.

The spoilers extend all the way to the outboard ailerons. They should be visible in that video. They should deploy with reversers even if not armed, right?

Here's how it should look:
http://www.jetphotos.net/viewphoto.p...864583&nseq=43

The photo below shows the outboard spoilers are retracted and the reversers are open.

[MCM]

The spoilers extend all the way to the outboard ailerons. They should be visible in that video. They should deploy with reversers even if not armed, right?

Assuming it is like all of the other Boeing aircraft, yes that is correct - selection of reverse thrust should activate the spoilers even if they are not armed.

Unless there is a known (or unknown) unservicablity in the system.

[aardvark2zz]

aardvark2zz >> looks like some failure is possibly responsible

NTSB ISSUES SECOND UPDATE ON JACKSON HOLE B-757 RUNWAY OVERRUN INCIDENT

In its continuing investigation of the runway overrun of a jetliner in Jackson Hole, Wyoming, the National Transportation Safety Board has developed the following factual information:

At about 11:38 am MT on Wednesday, December 29, American Airlines flight 2253, a B-757-200 (N668AA) inbound from Chicago O'Hare International Airport, ran off the end of runway 19 in snowy conditions while landing at Jackson Hole Airport. No injuries were reported among the 181 passengers and crew on board.

Instrument Flight Rules (IFR) weather conditions prevailed around the time of the incident with a ceiling of 400 feet, light snow and visibility of 1 mile. Winds were 10 knots from 240 degrees. Runway friction measurement data obtained before and after the event have been provided by the Jackson Hole Airport Authority for further evaluation by the NTSB.

In the continuing investigation, work groups have been formed to examine the subject areas of air traffic control, airports, meteorology, flight crew operations, airworthiness, maintenance records, cockpit voice recorder (CVR), flight data recorder (FDR), and airplane performance.

The NTSB systems investigator conducted testing on the incident airplane from December 31, 2010, through January 6, 2011. Operational testing and examination was accomplished on the spoiler/auto speed brake, air/ground, autobrake, and thrust reverser systems. No discrepancies were found in the air/ground, autobrake, and thrust reverser systems. Examination of the auto speed brake mechanism in the cockpit pedestal found that the linear actuator aft attachment was improperly installed and was missing a bushing. This loose connection allowed the cam to be rotated slightly relative to the switch, which could cause the switch roller and the notch in the cam to not always align. System operation with this condition present is being investigated.

The maintenance group convened at the American Airlines facility in Tulsa, Oklahoma, to review airplane logbooks. The group focused primarily on the spoiler/speed brake, air/ground, and thrust reverser systems. No significant issues with any of these systems were recorded prior to the incident, and there were no open minimum equipment list (MEL) items at the time of the incident. The airplane was manufactured in June 1992 and, at the time of the incident, had accumulated 58,879 hours and 20,518 cycles. No discrepancies were noted during the last periodic service maintenance check conducted on December 26, 2010. The last heavy maintenance was accomplished in October 2005. The auto speed brake actuator was replaced in January 2008.

The CVR group convened on January 4, 2011, at the NTSB recorder laboratory. The group completed a transcript of the last 30 minutes of the recording and a summary of the previous 90 minutes. The transcript will be released when the public docket is opened.

The FDR group has begun the process of determining which of the documented parameters are installed and should be functional, and is checking the recorded data for validity. The group has verified the following factual information:

* The FDR download contains the last 43.9 hours of data, more than the required 25 hours, and includes all of the incident flight.
* The recorded speed brake handle position indicates that the speed brakes were manually extended by the flight crew during the approach after which the handle was left in the armed position until landing. The FDR records only the speed brake handle position and not the individual speed brake (spoiler) panel positions.
* The FDR data indicate that the aircraft touched down at approximately 132 knots.
* At touchdown, the air/ground parameter changes to "ground" for approximately one second and then switches to "air" for approximately ½ second before changing back to "ground" for the remainder of the recording.
* During the time period when the air/ground parameter switched back to "air," the speed brake handle position momentarily moved toward the down position and then returned to the armed position where it stayed for the remainder of the recording.
* Thrust Reverser (T/R) discrete parameters indicate that the T/Rs moved into the in-transit position during the ½ second that the air/ground logic parameter indicated "air."
* The T/Rs remained in the in-transit position for approximately 10 seconds before transitioning to the stowed position for one second. The T/Rs then moved back to the in-transit position for an additional 6 seconds before becoming deployed.
* The T/R discrete parameters indicate that approximately 18 seconds elapsed from the time the T/Rs began moving until they were fully deployed.

Additionally, the team has examined security camera videos provided by the airport as well as a video of the landing taken by one of the passengers.
.
(Zeffy @ pprune)
.

[orangehuggy]

CVR:

http://dms.ntsb.gov/public%2F50000-5...8%2F476738.pdf

[Evan]

It certainly reads like a mechanical failure of the reversers or the levers. Funny, after the event, they seem very deliberate about stating their innocence. I wonder, do the pilots think "CVR" in this situation?

[Gabriel]

I remember the overun at Chicago Midway, a 737NG, they also had trouble to move the levers into reverse. A child in a car was killed when the plane smashed it.

[3WE]

Originally Posted by Evan

It certainly reads like a mechanical failure of the reversers or the levers. Funny, after the event, they seem very deliberate about stating their innocence. I wonder, do the pilots think "CVR" in this situation?

After participating in a major, serious incident, I could easily see two folks reviewing thier actions verbally- in classic checklist style- and if you made the right choices, you made the right choices.

It could just be natural as opposed to a performance.

[MCM]

G'day Evan,

Nah, that was two guys who'd just had the fright of their lives trying to work out why they were sitting off the end of a runway when they had given a lot of consideration to ensuring they stopped.

After anything out of the ordinary you go back through your mind checking that you did everything correctly... thats all they were doing.

The adrenaline is pumping far too hard to be thinking about the CVR and making it sound "good" that soon after an accident.

[Fear_of_Flying]

I found that transcript to be very interesting, and slightly odd. A few things that struck me initially:

- It was clear that the pilot in particular was extremely apprehensive about the approach and the landing. Yet to make that announcement to the passengers about just hoping to get it down in one piece (to paraphrase) seems to have been an unfortunate choice. As a passenger, I would have been uneasy hearing that announcement. It's not as if he was just kidding around, it was more "half in jest, fully in earnest."

- There seems to have been a slightly delayed reaction by the pilots in confirming the safety of the passengers, with the initial reaction being more focused on themselves, their performance, and their future. Then they tried to explain what happened to the passengers, which also seemed a tad strange. Let's reassure the passengers first, get them safely off the plane, and worry about what happened later.

- As it turns out, there seem to have been some mechanical failures, but also, inevitably, a misstep or two by the pilots, for example, not manually deploying the speed brakes. It's hard to imagine that such an oversight would mean the end of their careers since it seems clear they were intent on making a safe landing and did almost everything correctly (such as speed and location of touchdown). But I'm sure every pilot knows - and hence the pilot's remarks upon coming to a stop - that when something goes wrong, regardless of the cause, his career is on the line, since pilot error is virtually a given as a contributing factor at least. But who does everything perfectly under such pressure? Not even Sully.

[Evan]

Originally Posted by Fear_of_Flying

Yet to make that announcement to the passengers about just hoping to get it down in one piece (to paraphrase) seems to have been an unfortunate choice. As a passenger, I would have been uneasy hearing that announcement.

I don't think that is a fair paraphrase. He was telling the pax to expect a hard landing, and not to be alarmed by it, which I think is quite considerate. He also tells them that this is quite normal for "a mountain landing".

- There seems to have been a slightly delayed reaction by the pilots in confirming the safety of the passengers, with the initial reaction being more focused on themselves, their performance, and their future. Then they tried to explain what happened to the passengers, which also seemed a tad strange. Let's reassure the passengers first, get them safely off the plane, and worry about what happened later.

Again, not fair at all. The first thing they did after getting the thing to stop was to get the ground crew moving and make sure the passengers stayed put:

11:38:32.4 RDO-1
call the ground crew.
11:38:35.0 PA-1
flight attendants stay in the airplane passengers stay in the airplane.

and only then...

11:38:40.0 HOT-1
what happened?
11:38:41.3 CAM-2
I didn't get * - auto * - I couldn't pull-

- As it turns out, there seem to have been some mechanical failures, but also, inevitably, a misstep or two by the pilots, for example, not manually deploying the speed brakes. It's hard to imagine that such an oversight would mean the end of their careers since it seems clear they were intent on making a safe landing and did almost everything correctly (such as speed and location of touchdown). But I'm sure every pilot knows - and hence the pilot's remarks upon coming to a stop - that when something goes wrong, regardless of the cause, his career is on the line, since pilot error is virtually a given as a contributing factor at least. But who does everything perfectly under such pressure? Not even Sully.

I don't know the Boeing procedures, but I think the memory items for a braking anomaly should include manual ground spoiler deployment. HOWEVER, the spoilers were armed (and called out), they had no evidence to suspect a deployment failure, and (AFAIK) raising the reverser levers on the 757 is a de facto manual extension of the ground spoilers (assuming maintenance hasn't hexed them). If, as the CVR seems to indicate, they could not move the levers, than yes, I think the instinct should have been to manually deploy the ground spoilers while working on the reverser levers, but given only a few seconds of reaction time and the the confusion involved, I would expect a human pilot to spend that time focused on steering and getting the reversers to deploy. Human factors being what they are.

What impresses me about the CVR is the level of communication going on between the crew. These pilots were definitely precautionary, vigilant and in the game the entire time.

Too bad their maintenance wasn't.

[MCM]

FoF,

I don't get your paraphrase at all.

The PA made during flight was a perfectly reasonable one. It was just letting the passengers know that they could expect a firm touchdown and a strong braking force. If you haven't experienced that before and weren't expecting it, it could be very startling. I read nothing into that PA at all.

The PA's made after landing were not perhaps the most eloquent, however these guys had the fright of their lives. They were sitting in an aeroplane with no obvious major damage, and had no reason to be immediately concerned. The PA to remain on the aircraft was swift, and they were ascertaining the status of the cabin within one minute or so... I think thats pretty good work.

You'll notice the word "Deployed" in the transcript - this is possibly a call that the speedbrake has deployed, even though in the event it has not. This error would not surprise me, as the sound of the speedbrake extending is quite often a subconcious cue that it has, and if the aircraft skips a little (ie goes back into air mode for a short period) the speedbrake will auto-stow, then should deploy again with the reversers.

Two questions which will be asked are: Should the airline policy allow landings on critical runways with poor braking action reported, and should the F/O have been the pilot flying for the landing.

[Evan]

Originally Posted by MCM

Two questions which will be asked are: Should the airline policy allow landings on critical runways with poor braking action reported, and should the F/O have been the pilot flying for the landing.

1) No. Not because it can't be done safely under normal circumstances, but because it leaves insufficient contingency for braking system failures, and aviation safety should always be about expecting failures (fault tolerance).

2) The F/O seems very capable to me, but there is this strange exchange (I'm assuming CAM-1 is the captain):

11:41:33.3 HOT-2
no we were sliding and uh uh I couldn't get the thrust reverser would not come out they were stuck.
11:41:39.7 CAM-1
that's why I tried * gimme the thrust reversers you wouldn't give 'em to me yeah.
11:41:41.3 HOT-2
and I went back and um pulled again and we would not could not get thrust reversers.

Here is the actual exchange he is referring to:

11:37:48.0 HOT-2
no reverse [voice sounds strained].
11:37:48.8 HOT-1
I got it.
11:37:49.4 HOT-1
get the (rers) get the reverse.
11:37:51.1 HOT-1
I got it you steer.
11:37:51.1 HOT-2
I can't get it.
11:37:52.9 HOT-2
I'm steerin'.

So it appears to me that the captain called out for control of the reversers twice and the F/O didn't release them. Although, if they were stuck, they were stuck, and so this would have made no difference.

[Fear_of_Flying]

Originally Posted by MCM

FoF,

I don't get your paraphrase at all.

The PA made during flight was a perfectly reasonable one. It was just letting the passengers know that they could expect a firm touchdown and a strong braking force. If you haven't experienced that before and weren't expecting it, it could be very startling. I read nothing into that PA at all.

I'm not sure your paraphrase quite captures the moment either, so let's look at the actual words:

ah there's also one other thing I would like to mention going to Jackson Hole if you've not been here before relatively short runway up here in the mountains it’s been snowing today we don't ah try and make a smooth landing here at Jackson Hole we just ah put the aircraft ah on the runway very quickly and firmly and go into full reverse and then use a heavy amount of braking make sure we stop in the first ah part of the runway so ah just be aware of that that's normal procedure for a mountain airport.

(My bold). In retrospect, this message conveys some of the pilot's genuine safety concerns at the time. It's not just a short mountain runway, it's also been snowing. We know why he wants to stop in the first part of the runway, not because it's normal procedure necessarily, but because he knows there's no traction in the last part of the runway. Hence, this announcement veils only partially his actual apprehensions, and I think the tone of that comes through in his words. To me, it goes a little beyond routine. That's all, not an indictment, just an observation.

[Fear_of_Flying]

Originally Posted by Evan

I don't know the Boeing procedures, but I think the memory items for a braking anomaly should include manual ground spoiler deployment. HOWEVER, the spoilers were armed (and called out), they had no evidence to suspect a deployment failure, and (AFAIK) raising the reverser levers on the 757 is a de facto manual extension of the ground spoilers (assuming maintenance hasn't hexed them).

Interesting to note that when asked to review the transcript, the pilot's only addendum was to note that one of the clicks alluded to was the sound of the spoilers deploying, clearly giving a case for why he didn't deploy them manually. However, I also read that it is indeed a procedure (I believe from the airline) to manually deploy them upon encountering a braking anomaly. While I totally agree with you, the pilots seemed competent, communicated well, and did everything to the best of their ability, I think it will nevertheless be determined that they did not follow the prescribed procedure, and this contributed to the accident. That is an unfortunate inevitability of these investigations it seems, but then again, you're kind of a stickler for following memory items I thought.

[Evan]

Originally Posted by Fear_of_Flying

]That is an unfortunate inevitability of these investigations it seems, but then again, you're kind of a stickler for following memory items I thought.

I don't think there is a memory item procedure for reverser failure. If there is, then these guys should get tagged for it. I think this is one of those cases of a mechanical fault confusing the situational awareness. Ground spoilers were armed, so they should have come up even without the reversers deploying. We still don't know why they didn't, but it sounds like there was some mechanical issue with the pedestal controls.

But it should be trained as a memory item in the future: when encountering reverser anomaly, manually extend ground spoilers, then work the problem.

[orangehuggy]

as there was no gross negligence or intent to harm, there should not or would not be any negative impacts on the pilots' careers. this is a great thing that happened, after thorough analysis many important safety related concepts will be learned and contribute to minimizing future overrun occurrences - and no one got hurt!

[Deadstick]

Not being anywhere close to a professional pilot myself, I read the transcript seeing their actions and communications as completely thorough and professional.

[Fear_of_Flying]

Originally Posted by Evan

I don't think there is a memory item procedure for reverser failure. If there is, then these guys should get tagged for it. I think this is one of those cases of a mechanical fault confusing the situational awareness. Ground spoilers were armed, so they should have come up even without the reversers deploying. We still don't know why they didn't, but it sounds like there was some mechanical issue with the pedestal controls.

But it should be trained as a memory item in the future: when encountering reverser anomaly, manually extend ground spoilers, then work the problem.

I'm not sure what counts as an officially designated memory item, but a procedure that you're supposed to carry out in the event of an abnormal landing strikes me as something that would be the same thing for all practical purposes.