AirbusMDCFAN
Topic Author
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Final NTSB report on DL 1086 @ LGA

Sun Mar 05, 2017 3:20 pm

Source/Link: http://www.avherald.com/h?article=482b659f/0004&opt=0

The NTSB has issued it's final report on the March 5th, 2015 runway excursion of N909DL operating DL 1086
into KLGA.
Pilot issues appear to the cause. Some of the findings include:

On Mar 4th 2017 the NTSB released their final report concluding the probable causes of the accident were:

The National Transportation Safety Board determines that the probable cause of this accident was the captain’s inability to maintain directional control of the airplane due to his application of excessive reverse thrust, which degraded the effectiveness of the rudder in controlling the airplane’s heading.

Contributing to the accident were the captain’s
(1) situational stress resulting from his concern about stopping performance and
(2) attentional limitations due to the high workload during the landing, which prevented him from immediately recognizing the use of excessive reverse thrust.
 
MKEdude
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Re: Final NTSB report on DL 1086 @ LGA

Sun Mar 05, 2017 5:07 pm

What became of the pilots? Did they get canned outright, or are they still flying?
"You can't be a real country unless you have a beer and an airline." Frank Zappa
 
bennett123
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Re: Final NTSB report on DL 1086 @ LGA

Sun Mar 05, 2017 5:23 pm

I assume N909DL has now been parted/scrapped.

They were lucky that the fence held.

If not, they would have been in the drink.
 
jetmatt777
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Re: Final NTSB report on DL 1086 @ LGA

Sun Mar 05, 2017 7:06 pm

MKEdude wrote:
What became of the pilots? Did they get canned outright, or are they still flying?


Likely sent for some additional training and some mental evaluations (recovering from a crash) and then back on the line.
Lighten up while you still can, don't even try to understand, just find a place to make your stand and take it easy
 
26point2
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Re: Final NTSB report on DL 1086 @ LGA

Sun Mar 05, 2017 8:48 pm

Odd that the captain would insist on flying this ATL-LGA leg when leg rotation would have had SIC (with equal experience) flying. Ego? Seems to me SIC was way ahead of the situation but not his leg and not much he could do but advise and hold on. Good for him to do what he did though.
 
Newbiepilot
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Re: Final NTSB report on DL 1086 @ LGA

Sun Mar 05, 2017 9:00 pm

MKEdude wrote:
What became of the pilots? Did they get canned outright, or are they still flying?


I hope they were not canned and just retrained. I expect Delta to not blame crews like that.

The crew was stressed and got some incorrect information regarding brake performance. The captain may have advanced the throttles too far in reverse thrust while simultaneously dealing with the spoilers not deploying and auto braking not activating. The first officer noticed and identified the problem and the captain responded after a few seconds. While there were a number of errors, you can't entirely blame the crew. They were right at the edge of operation limits. A crosswind with moderate braking action and a tailwind near minimum visibility is not easy to deal with, especially when You are told to expect good braking action.
 
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SaveFerris
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Re: Final NTSB report on DL 1086 @ LGA

Sun Mar 05, 2017 9:28 pm

26point2 wrote:
Odd that the captain would insist on flying this ATL-LGA leg when leg rotation would have had SIC (with equal experience) flying. Ego? Seems to me SIC was way ahead of the situation but not his leg and not much he could do but advise and hold on. Good for him to do what he did though.


"The ATSB reported the captain (56, ATPL, 15,200 hours total, 11,000 hours on type) was pilot flying - even though he had also flown the outbound sector to Atlanta, then decided due to the poor weather conditions he would fly the sector back to LGA, too -, the first officer (46, ATPL, 11,000 hours total, 3,000 hours on type) was pilot monitoring."

The captain had considerably more time in type which can be more important than total time, especially when things start to go wrong. In my experience, most of the time the conditions are that poor the captain elects to fly the leg as they are the ultimately responsible for the operation of the aircraft.
 
26point2
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Re: Final NTSB report on DL 1086 @ LGA

Sun Mar 05, 2017 10:51 pm

Yes. Clearly the captain, with 11000 hours in type, was qualified but there is no doubt the dude in right seat with a measly 3000 hours in type was far ahead of the game during crash sequence and, as it should have been his leg anyway, could have prevented this accident if he was the flying pilot.
 
NBGSkyGod
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Re: Final NTSB report on DL 1086 @ LGA

Sun Mar 05, 2017 11:08 pm

Also this:

The captain decided to continue the approach to a landing because he and the first officer had determined that the landing criteria had been met, including the landing distance performance requirements for good braking action. The captain called the runway in sight as the airplane descended through an altitude of about 233 feet agl. Besides company and ATIS reports indicating that the runway was plowed, sanded, and chemically treated and was wet with snow, the flight crew had overheard ATC stating, as late as 1040, that arriving airplanes were being held for runway cleanup. The first officer stated that these communications “painted a picture” of what he and the captain could expect to see once the airplane broke out of the clouds—a runway that had at least some patches of runway surface visible. However, the captain and the first officer reported that the runway appeared white rather than dark or patchy, which was not with their expectations regarding the nature and extent of the contamination on the runway given the recent snow cleaning operations and the reports of good braking action. Delta’s MD-88/90 operating procedures for adverse weather indicated that, “when there is contamination on the runway…captains must evaluate crew, aircraft, and environmental conditions in determining the safety of operating their flight.” Key environmental conditions included braking action reports, the nature of contamination (water, wet snow, or dry snow), and the depth of the contamination. The flight crew knew that two preceding airplanes had reported good braking action on the runway. However, it would have been difficult for the crew to visually assess the nature and depth of the snow on the runway. Also, little time was available for the flight crew to reevaluate the decision to continue. Only 13 seconds had elapsed between the time that the captain called the runway in sight and the time of the 50-foot automated callout, when the captain would have been preparing to flare the airplane. During these 13 seconds, the captain was engaged in several tasks, including adjusting the aim point to land closer to the approach end of the runway, decrabbing the airplane to align its longitudinal axis with the runway, and making aileron inputs to correct for drift. The NTSB concludes that, even though the flight crewmembers’ observations of snow on the runway were inconsistent with the expectations that they formed based on the field condition information that they received, their decision to continue the approach was not inappropriate because the landing criteria had been met.
Pilots are idiots, who at any given moment will attempt to kill themselves or others.
 
Flighty
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Re: Final NTSB report on DL 1086 @ LGA

Sun Mar 05, 2017 11:23 pm

26point2 wrote:
Yes. Clearly the captain, with 11000 hours in type, was qualified but there is no doubt the dude in right seat with a measly 3000 hours in type was far ahead of the game during crash sequence and, as it should have been his leg anyway, could have prevented this accident if he was the flying pilot.


So what do you think should have happened that day? They should switch ranks? Why, just based on your opinion?
 
HoangLe
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Re: Final NTSB report on DL 1086 @ LGA

Sun Mar 05, 2017 11:47 pm

The pilots saved the aircraft and the passengers. No matter what happened, in the end the important thing is saving lives and they did a great job. I am amazed that people complaining and blaming them? Try to fly in that situation before start blaming.
In addition, those long, very long reports that draw the picture of the event, it takes you minuteS to read but up there it happened in few seconds.

Don't just read NTSB reports and judge the situation, pilots are in the cockpit for people to blame when things go wrong.
 
26point2
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Re: Final NTSB report on DL 1086 @ LGA

Sun Mar 05, 2017 11:59 pm

NBGSkygod claims: "Pilots are idiots...". Let's be clear...anyone who feels it necessary to call themselves SkyGod must think highly of themselves. Good for you. Evidently you have made up your mind.

You also claim " I also noticed you said nothing about the fact the BRA had degraded from GOOD to POOR on a contaminated runway". Where does it say this? Did you read the report SkyGod?
 
NBGSkyGod
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Re: Final NTSB report on DL 1086 @ LGA

Mon Mar 06, 2017 12:15 am

26point2 wrote:
NBGSkygod claims: "Pilots are idiots...". Let's be clear...anyone who feels it necessary to call themselves SkyGod must think highly of themselves. Good for you. Evidently you have made up your mind.

You also claim " I also noticed you said nothing about the fact the BRA had degraded from GOOD to POOR on a contaminated runway". Where does it say this? Did you read the report SkyGod?

You are correct, I misread the report, should be MEDIUM on a contaminated runway. However, the rest of my comment stands.
Pilots are idiots, who at any given moment will attempt to kill themselves or others.
 
26point2
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Re: Final NTSB report on DL 1086 @ LGA

Mon Mar 06, 2017 12:30 am

Sky God sez "Pilots are idiots.."

Dude....what have you been smoking? There is no report of "medium" braking action. Only PIREPS of Good braking action.
 
NBGSkyGod
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Re: Final NTSB report on DL 1086 @ LGA

Mon Mar 06, 2017 1:04 am

26point2 wrote:
Sky God sez "Pilots are idiots.."

Dude....what have you been smoking? There is no report of "medium" braking action. Only PIREPS of Good braking action.


The accident airplane was the fifth arrival on runway 13 after it was last cleared. During this time, one report of medium braking action at the touchdown zone was received about 19 minutes before the accident landing, and reports of good braking action were received about 16 and 8 minutes before the accident landing. Because braking action reports are inherently subjective, the NTSB considered the results of the simulations it conducted with Boeing as part of this accident investigation. The simulations showed that the wheel braking coefficient for the accident airplane was, at a minimum, consistent with the description of medium braking action in AC 25-32 and that the Delta MD-88 that landed uneventfully on runway 13 just before the accident landing had a similar wheel braking coefficient. In addition, the flight crew of the MD-88 airplane that landed on runway 13 just before the accident landing did not report any adverse landing conditions. Thus, the NTSB concludes that, although the runway was contaminated with snow, runway friction when the accident airplane landed was sufficient for stopping on the available runway length.
Pilots are idiots, who at any given moment will attempt to kill themselves or others.
 
Cubsrule
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Re: Final NTSB report on DL 1086 @ LGA

Mon Mar 06, 2017 3:25 am

NBGSkyGod wrote:
The simulations showed that the wheel braking coefficient for the accident airplane was, at a minimum, consistent with the description of medium braking action in AC 25-32 and that the Delta MD-88 that landed uneventfully on runway 13 just before the accident landing had a similar wheel braking coefficient. In addition, the flight crew of the MD-88 airplane that landed on runway 13 just before the accident landing did not report any adverse landing conditions. Thus, the NTSB concludes that, although the runway was contaminated with snow, runway friction when the accident airplane landed was sufficient for stopping on the available runway length."


This has shades of SWA1248, who also likely had enough runway to stop if everything had gone exactly according to plan post-touchdown. So what is the solution? Changing the braking action assumptions? Tighter parameters (e.g. on tailwind component)? Something else?
I can't decide whether I miss the tulip or the bowling shoe more
 
NBGSkyGod
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Re: Final NTSB report on DL 1086 @ LGA

Mon Mar 06, 2017 4:10 am

The way I read the report, was short of the Tower not issuing correct surface information, and the pilot not getting on the reverses so aggressively, there wasn't much that could be changed. The conditions were deteriorating rapidly, the crew was faced with a picture that was vastly different from the one they were lead to believe existed with only a few seconds to react during a very difficult time. The crew had about 13 seconds after breaking out of the clouds and seeing the runway and maneuvering into the flare (according to the report) to observe, recognize, determine, and decide. Really this accident comes down to a lot of human factors. It could have been prevented, but there were a lot of things that happened all at once, and likely won't occur again. Thankfully there was no loss of life and very little damage (other than the poor fence and the MD-88).
Pilots are idiots, who at any given moment will attempt to kill themselves or others.
 
INFINITI329
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Re: Final NTSB report on DL 1086 @ LGA

Mon Mar 06, 2017 4:50 am

Maybe someone a little smarter than me can explain this... why stop using reserve thrust at 110K? In those conditions, I would expect them to be used until the airplane is brought down to a much lower speed where brakes are more effective but Im guessing here
 
737tanker
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Re: Final NTSB report on DL 1086 @ LGA

Mon Mar 06, 2017 11:10 am

Skygod
Your report of medium braking comes from simulations done during the investigation. The only reports that the crew had was of good braking.
 
Newbiepilot
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Re: Final NTSB report on DL 1086 @ LGA

Mon Mar 06, 2017 1:25 pm

The crew had reports of good braking action and that the runway had been treated. Neither of those were true.

If I reed the report correctly, the crew landed a plane that was not capable of landing safely on the runway due to the conditions. They had been told the conditions were adequate. While it probably was possible to land in those conditions, adding in excessive reverse thrust, delayed spoilers and autobrakes and poor visibility while flying in a crabbed position due to a tailwind and crosswind, i think it can't be assumed that pilots can successfully land like that.
 
Newbiepilot
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Re: Final NTSB report on DL 1086 @ LGA

Mon Mar 06, 2017 1:28 pm

INFINITI329 wrote:
Maybe someone a little smarter than me can explain this... why stop using reserve thrust at 110K? In those conditions, I would expect them to be used until the airplane is brought down to a much lower speed where brakes are more effective but Im guessing here


Reverse thrust looses effectivity as an airplane slows since thrust is not actually backwards. Usually it is only used above 60-80 knots, but the MD80 has a small rudder and the air flow is different than wing mounted engines.
 
tinpusher007
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Re: Final NTSB report on DL 1086 @ LGA

Mon Mar 06, 2017 1:46 pm

Also, in this case it appears that 110kts is when they began losing directional control and the FO seemed to recognize that it was due to rudder blanking by the thrust reversers.
"Flying isn't inherently dangerous...but very unforgiving of carelessness, incapacity or neglect."

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