Pegasus Airlines Boeing 737-800 TC-CPF overrun runway at Trabzon. All pax okay
Incident may have similarities with these -
747-8driver mentioned one of them.
Both fly by wire Airbusses, twins with one thrust reverser known to be inoperable and an elevated thrust after touchdown from the non-reversed engine.
[1]
March 22, 1998
Airbus A320-214
Fatalities 3 on ground
https://en.wikipedia.org/wiki/Philip...nes_Flight_137
http://www.rvs.uni-bielefeld.de/publ...olodReport.pdf
"condition of the aircraft immediately upon touch down with No. 1 engine reverse inoperative, thereby causing an adverse flight condition of extreme differential power application during the landing roll resulting in runway excursion and finally an overshoot"
"3) Review the Airbus A320 flight technique for landing with one engine reverse inoperative, amend/revise as necessary;"
[2]
July 17, 2007
Airbus A320-233
Fatalities 199 (all 187 on board; 12 on the ground)
https://en.wikipedia.org/wiki/TAM_Airlines_Flight_3054
https://web.archive.org/web/20110706...df/3054ing.pdf
http://www.dailymotion.com/video/x4m6hr1 -- Mayday _ Air Crash Investigation S11E01 - Deadly Reputation (TAM Airlines Flight 3054)
"The deactivated thrust reverser on the number 2 engine was confirmed"
"the flight computer recorded the left thrust lever being retarded to the rear-most position, activating the thrust reverser on the left engine, while the right thrust lever (controlling the engine with the disabled thrust reverser) remained in the CL position."
"As a matter of fact, there are various reports of errors in the execution of the pinned
reverser landing procedures, and these incidents are not restricted to the aircraft of this
manufacturer. It is a problem that occurs throughout the aircraft industry. "
747-8driver mentioned one of them.
Both fly by wire Airbusses, twins with one thrust reverser known to be inoperable and an elevated thrust after touchdown from the non-reversed engine.
[1]
March 22, 1998
Airbus A320-214
Fatalities 3 on ground
https://en.wikipedia.org/wiki/Philip...nes_Flight_137
http://www.rvs.uni-bielefeld.de/publ...olodReport.pdf
"condition of the aircraft immediately upon touch down with No. 1 engine reverse inoperative, thereby causing an adverse flight condition of extreme differential power application during the landing roll resulting in runway excursion and finally an overshoot"
"3) Review the Airbus A320 flight technique for landing with one engine reverse inoperative, amend/revise as necessary;"
[2]
July 17, 2007
Airbus A320-233
Fatalities 199 (all 187 on board; 12 on the ground)
https://en.wikipedia.org/wiki/TAM_Airlines_Flight_3054
https://web.archive.org/web/20110706...df/3054ing.pdf
http://www.dailymotion.com/video/x4m6hr1 -- Mayday _ Air Crash Investigation S11E01 - Deadly Reputation (TAM Airlines Flight 3054)
"The deactivated thrust reverser on the number 2 engine was confirmed"
"the flight computer recorded the left thrust lever being retarded to the rear-most position, activating the thrust reverser on the left engine, while the right thrust lever (controlling the engine with the disabled thrust reverser) remained in the CL position."
"As a matter of fact, there are various reports of errors in the execution of the pinned
reverser landing procedures, and these incidents are not restricted to the aircraft of this
manufacturer. It is a problem that occurs throughout the aircraft industry. "
If that was what happened, then it's not the first time a runway excursion incident has resulted from a go-around aborted by the captain when the FO was PF. QF 1 at Bangkok in 1999 was in similar circumstances. Aborted go-arounds are never a good idea.
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Dont know if that is a guess or a statement though.
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and physically hold both of them closed against the servos all the way to the flare; then hold them closed all the way down the runway until releasing just one of them prior to the excursion?
Last edited by Future Rodney King; 16th Jan 2018 at 12:09.
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Grossly simplifying it ...and in general ... Inop is allowed because the thrustreversers are technically an 'extra'. Operationally you could/should be able to do without them. You might take a look for example at how required landing distances are calculated for each flight.
You might say that is from a safety point of view. But add to that that a 'braking' backup is 'nice'.
From an operational point of view there are advantages in 'taking an exit earlier'.
With Murhpy in mind you might say that every added feature creates added types of errors, incidents and accidents. That is true for basic and safety features. Like an ELT (battery) malfunction burning a hole through a 787 fuselage. Or an escape slide inflating inside the cabin and blocking an exit.
So Murphy is not surprised that a reverser inop with a potential asymmetry can lead to an actual asymmetry event. In spite of the multiple layers of defensive safeguards.
Overall the balance is positive, thats why they are on, and why you are allowed to fly with one locked under specified conditions and procedures.
Again, grossly simplified, but hope it gives an idea about some of the factors involved.
You might say that is from a safety point of view. But add to that that a 'braking' backup is 'nice'.
From an operational point of view there are advantages in 'taking an exit earlier'.
With Murhpy in mind you might say that every added feature creates added types of errors, incidents and accidents. That is true for basic and safety features. Like an ELT (battery) malfunction burning a hole through a 787 fuselage. Or an escape slide inflating inside the cabin and blocking an exit.
So Murphy is not surprised that a reverser inop with a potential asymmetry can lead to an actual asymmetry event. In spite of the multiple layers of defensive safeguards.
Overall the balance is positive, thats why they are on, and why you are allowed to fly with one locked under specified conditions and procedures.
Again, grossly simplified, but hope it gives an idea about some of the factors involved.
Last edited by A0283; 17th Jan 2018 at 00:44. Reason: Typo
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When landing on a contaminated runway with one locked, you have to be on your "A" game.
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Differential thrust with one inoperative thrust reverser isn't a big deal. It's something to be aware of but not something to be afraid of.
A damp runway isn't contaminated. With contaminated runways, with snow, sleet, slush, on the runway, you need to be very careful using differential thrust. The MEL may prohibit operation into contaminated runways with an inoperative thrust reverser.
It's hard to understand how an engine power was advanced enough to cause a runway excursion. It happened. Professional pilots are puzzled since the Captain's hand is typically on the throttles ensuring that they're at idle and remain at idle.
A damp runway isn't contaminated. With contaminated runways, with snow, sleet, slush, on the runway, you need to be very careful using differential thrust. The MEL may prohibit operation into contaminated runways with an inoperative thrust reverser.
It's hard to understand how an engine power was advanced enough to cause a runway excursion. It happened. Professional pilots are puzzled since the Captain's hand is typically on the throttles ensuring that they're at idle and remain at idle.
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Differential thrust with one inoperative thrust reverser isn't a big deal. It's something to be aware of but not something to be afraid of.
It helps if you let the auto brakes do their thing and not disconnect too early; then all you have to do is steer with your feet: heels on the ground. Considering the length of the runway, and the need for 180, there should not be any need to disconnect the AB's. I'm not understanding the thoughts about mis-selecting TOGA, or flaps up knocking the Rt. TL to forward thrust, or some other curious 'what ifs'. They were so far down the runway, and judging by the tip over the edge, they must have been going quite slowly and just nudged over the edge, otherwise they were swimming. The skid marks from the mains suggest some heavy stopping forces. As has been said, the investigators have all the info they could wish for and must surely have the answers. When will they tell the rest of us is the question.
It helps if you let the auto brakes do their thing and not disconnect too early; then all you have to do is steer with your feet: heels on the ground. Considering the length of the runway, and the need for 180, there should not be any need to disconnect the AB's. I'm not understanding the thoughts about mis-selecting TOGA, or flaps up knocking the Rt. TL to forward thrust, or some other curious 'what ifs'. They were so far down the runway, and judging by the tip over the edge, they must have been going quite slowly and just nudged over the edge, otherwise they were swimming. The skid marks from the mains suggest some heavy stopping forces. As has been said, the investigators have all the info they could wish for and must surely have the answers. When will they tell the rest of us is the question.
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Track across grass seems straight
It is curious to me that the tracks across the grass from where the airplane apparently departed the runway pavement to the edge of the down-sloping bank seem to be very straight. That indicates to me that whatever forces caused the yawing moment resulting in the deviation from runway centerline were active only when the airplane was on the runway and did not continue as it crossed the grass. If the problem resulted from stuck nose gear steering or asymmetric thrust I would think that the track across the grass would be curved. It is possible, however, that turning side force from a stuck nose gear would not continue onto the soft margin if the nose gear stopped rolling as it dug into to the dirt. Even if that were the case, I would think that an airplane departing the runway with any significant yaw rate would exhibit continued yaw motion (and thus curved tracks) during at least the first part of its motion off the edge of the runway.
I sure hope those data and voice recorders are released so that we can learn from this incident and reduce the likelihood of a repeat.
I sure hope those data and voice recorders are released so that we can learn from this incident and reduce the likelihood of a repeat.
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For once the Turkish Authorities are caught between a rock and a hard place. Normally we never get to hear the results of the investigations and Ali Sabanci won't want the "pegasus family" hung out to dry. On the other hand Boeing and CFM face severe commercial pressure to publish the results lest there is a call for CFM engined A/c and NGs to be grounded pending the resolution. Boeing stated uncommanded thrust INCREASE is a 1/100,000,000 hrs event, on the other hand DECREASES on thrust are quite common especially at high power in the climb. The Facts as we know them are: Cloudbase was below minima, FO was PF for most of the approach, Reverse was selected, and the centre line track not maintained after landing. From the "Flying Horses mouth" FO elected to GA and the flight somehow landed. Given the harsh regime in Turkey we are not surprised by the Pilot statements to the prosecutors, however, this event could have been a huge loss of life and the authorities have a duty to release the info, and in a timely manner. Good job its not US all PAX would be finding a lawyer by now..
I think you have things back-to-front.
There is no smoking gun implicating an uncommanded power increase. At this stage it is simply one of a number of hypotheses.
In the absence of that, there won't be any AD or fleet grounding.
There is no smoking gun implicating an uncommanded power increase. At this stage it is simply one of a number of hypotheses.
In the absence of that, there won't be any AD or fleet grounding.
Boeing and CFM face severe commercial pressure to publish the results
the absence of such speaks to the problem elsewhere in a final report, if any, by the authorities involved.
FCeng -- Conversely, the aircraft wouldn't have stayed on the runway very long with half, or even a quarter, of the heading deviation shown by those tracks. So there had to be a pretty significant yaw rate not long before the wheels hit the grass
