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Runway & cliff 'excursion' in Turkey

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There's that old much banded word again, "Nosedive" as used by reporters everywhere when they know nothing about aviation! It's a "Dive" end of! in this case it wasn't even that, the aircraft went off the runway and slid down a hill, It didn't dive anywhere, LOL. 

 Someone will have questions to answer clearly, thankfully  no-one was hurt but the  aircraft recovery will be interesting, if indeed they bother. It may well be scrapped on site looking at the state of it.

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Just a thought but looking at pictures of the skid marks* on the runway, it seems like the left main undercarriage brakes jammed causing the turn.

 

Seeing it I can't help thinking of  Michael Caine in the final scene of The Italian Job where the coach is hanging balanced over a cliff edge.  I imagine the crew saying. "Now 'old on.  Nobody move. I've got an idea."

 

* I bet there were other skid marks but not on the runway.

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All 162 passengers and crew, who were on board the aircraft when it overshot the runway on Sunday, were evacuated safely by emergency services. No one was hurt.

 

Don't they have lawyers in Turkey?  In the US, everyone would have had an injury and 50 bystanders would have jumped aboard after it came to a stop and claimed to be stowaways with injuries too.

 

John

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1 hour ago, allardjd said:

Don't they have lawyers in Turkey?

Yes but we are talking about a "shithole country" here John (well almost). :D

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I thought all the Turks had emigrated to Germany for the jobs?

 

John

 

EDIT:  All above in jest, of course.  Happy no one was hurt in what could have been a terrible disaster.  A little fire into the mix and there'd have been few survivors, if any.  I suspect the inflatable slides would not have been of much use in that situation.

 

JDA

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I'm just glad no one was hurt and the mud was soft enough to grab it. Why it happened? Shrug...black ice, pilot error, mechanical error?

 

 

 

 

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5 hours ago, Andrew Godden said:

So if I dive feet first, I guess that's called a "jump".

Yep, or a tailslide! LOL

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Don't know if all experienced the same thing - but what a papa oscar sierra video. Betcha that was a scary ride from the front seats.

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More info...

 

 
"On Jan 15th 2018 Trabzon's Prosecution Office reported they have opened an investigation into the accident. The flight crew was tested for intoxication, no findings were made, and was interviewed. The flight crew reported the flight was normal until after touch down with the first officer being pilot flying, deceleration was slow due to the wet runway, the controls were handed to the captain, the captain applied brakes, the aircraft turned left, the aircraft went off the runway, the right hand engine suddenly accelerated in forward thrust unintentionally. The aircraft went over the cliff and dropped, the right hand engine separated and fell into the sea. The aircraft came to a stop, the crew alerted tower and emergency services responded arriving in a short time."
 
"On Jan 16th 2018 Trabzon's Prosecution Office added the captain stated, that the first officer landed the aircraft, the aircraft however did not slow down during roll out. The captain took control of the aircraft and applied brakes, at this time the aircraft veered left, the right hand engine accelerated when the aircraft was already off the left edge of the runway. The aircraft ran over soft ground for some brief moments, then went over the cliff. The first officer reported that the weather was rainy, the runway was wet, the aircraft did not slow down after the wheels touched down. The aircraft veered to the left, the captain took control, the right hand engine accelerated. (Editorial note: there is no official confirmation of a thrust reverser being locked out as rumors on the Internet claim.)"
 
John

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That skid mark so far down jibes with their recount of the incident...there would have been a certain amount of "Oh Shit" occuring in the cockpit if they were still at speed that far down the runway...im betting a hasty/panic'd mis-grab at the throttles caused that right side engine to accelerate, adding to the OS-factor...but...

I'm hoping for their sake some fault is found in the equipment rather than procedures.  Crossing fingers for them.

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Aircraft stop on wet runways all the time, I'm not going to dismiss mechanical failures but me thinks something else happened or a combination of the two.

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I'm going to say human error is more likely than mechanical issues, though it could be either or both at once.   I'd have to go with someone not correctly setting up the automation (throttles, brakes, reversers, spoilers, etc.) and possibly also what Coff suggested with accidentally advancing the right throttle or going to reverse thrust on the left engine only.  I think it might be possible/plausible that one of them advanced the right throttle when reaching for the upper part of the lever to unlatch the reverse thrust.   

 

This is utter speculation, of course.

 

John

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Definitely have to agree that human error was the culprit. Can you imagine two guys frantically going about making a bad situation worse.

 

There's quite a lag to get a big jet to spool up. Odds are good that the reversers  (or likely just one of them), which don't need to wait for spool-up, are the issue.

 

With the CF going on in the cockpit I'd like to know which one of them was bracing himself against a rudder pedal whilst trying to get the reverser(s) into play.

 

Ah.......armchair aviators - ain't we great? I just feel sorry for the poor bu**ers who were on the wrong runway for a port side excursion.

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From the "It Could Have Been Worse" department...

 

Take a look at the terrain on the other side of the runway, a kind of embankment.  If they'd have veered that way I expect it would have ground-looped, at least and possibly cartwheeled or gone inverted.  

 

The biggest ICHBW factor, of course, was no fire.  It's been stated the runway was wet and might even have been raining, which certainly must have helped avoid a nightmare.  Can you imagine trying to evacuate that thing in the attitude it was sitting in with a fire going?

 

John

 

 

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One of a number of theories being kicked around at PPRUNE...

 

"First Officer is pf, weather is at minimums. They are expecting to see the runway at minimums. At minimums they see the runway and the first officer disengages the autopilot but at the same time he presses the toga buttons. Captain takes over and lowers the nose and retards both thrust levers to idle, they land at idle thrust and aircraft was dispatched with one reverser inop. The captain deploys the thrust reverser of the left engine and releases the right engine. Since he hadn't disconnect the auto throttle right engine goes to TOGA thrust. Aircraft starts to accelerate and skids off the runway from the left."

 

It is alleged in the PPRUNE comments and appears to be factual that the AC was dispatched with one Thrust Reverser inoperable.  Those guys seem to think that's fairly common and that you need to be conscious of it but not necessarily afraid of it.  Using one reverser with caution is possible and not generally prohibited.  Apparently rudder, nose wheel steering and/or differential braking (depending on speed) can keep you straight.  It can bite you if you screw the pooch, but it's not considered inherently unsafe.  Different airlines/aviation authorities treat it somewhat differently, but that view of it didn't seem to be challenged too severely by the PPRUNE crew.
 
The theory quoted above seems to hinge on the allegation that the PF (first officer), either deliberately or accidentally pushed the TOGA button(s?) at minimums but the Captain over-rode it and "saved" the landing (i.e. rejected the commanded go-around) by manually holding the throttle levers back against the Auto Throttle servos.  It's designed so crew can fairly easily overcome the servos if they choose to.  Unfortunately for the crew in this postulated scenario, once TOGA is commanded the Auto-Throttles will push to TOGA unless physically held back or Auto Throttle is canceled.  So, AC touched down, and was slowed.  When going pretty slow but with left Thrust Reverser still engaged, Captain lets go of the right throttle and the A/T dutifully pushes it to TOGA.  
 
There was one comment that the A/T is automatically disengaged two seconds after the "squat switch" senses the AC on the ground and that it would be necessary to push the TOGA button(s) again for the scenario to be played out as stated.  Only one commenter mentioned it and I couldn't sense whether the others agreed or not.  The discussion of the TOGA commanded thrust increase continued after his comment so I had the impression that the rest hadn't fully bought into it.
 
Statements by both pilots indicate "un-commanded" thrust increase on right engine, which is not inconsistent with the TOGA-induced Auto Throttle scenario quoted above. One fly in the ointment for that scenario is the spool-up time to get serious engine power, but it may not have taken much to cause the excursion.  This was around midnight in bad WX so that's another factor in play here - visual cues might not be have been all that great.
 
One interesting fact noted, which may or may not have any bearing on this particular event, is that Boeing Anti-Lock Braking disengages automatically when AC decelerates below 18 knots, introducing a possibility of some kind of locked brake event on the wet runway, though only at a pretty low speed.  A locked brake, either from a technical issue or a heavy foot while on a wet runway probably can't be ruled out.  The AB won't prevent it below 18 knots.
 
There is not a high degree of confidence expressed at PPRUNE that a clear and accurate report will ever see the light of day given a Turkish airline accident at a Turkish airport.

 

John

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Where the Pilots vs PPrune accounts differ:

 

The pilots claimed "the plane did not slow down" (indicating that the plane was on the runway for some amount of time, at least long enough for the nose wheel to touch down before any serious braking would have been applied) Then "The Captain took over"... Then "The right engine event occured". (..indicating there was some Pause between the landing contact, assessing that the aircraft was Not slowing down before the captain took over prior to the Engine incident).

 

The PPrune account assumes that the Captain immediately took over once it touched down, before the Nose Wheel touched, at which point afterwards he executed a series of actions that should have slowed the plane down, but instead helps cause the TOGA event, which then suddenly spooled up the Rt engine and careened off the runway. (Which in my opinion, from the exalted position of the infallible wannabee pilot's couch, seems like the Careen event would have occurred earlier down the runway if the PPRUNE account timing is correct.)

 

Edited by Captain Coffee

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3 hours ago, Captain Coffee said:

The PPrune account assumes that the Captain immediately took over once it touched down, before the Nose Wheel touched, at which point afterwards he executed a series of actions that should have slowed the plane down, but instead helps cause the TOGA event, which then suddenly spooled up the Rt engine and careened off the runway.

 

Actually, they are saying the Captain took the controls at minimums on the approach, several hundred feet above ground and probably a half mile or more out from the threshold.  He was in control for the remainder of the flight/event.  They are postulating that he didn't want to fly the go-around that the co-pilot had invoked, possibly by accident.

 

The PPRUNE guys seem to be pretty much in agreement that the AC went over the edge at a pretty low speed; if not they would have been treading water.  The consensus is that it barely teetered over.

 

The skid marks in the grass indicate that at least one set of main gear tires were locked.  There don't seem to be any skid marks on the runway but it was wet, so may not have left any even if a wheel was not turning.  The AC was approaching (actually pretty close to) a turn-around pad at the far end of the runway and they seem to be pretty much in agreement that this was a relatively low speed event that occurred at the far end of the runway.  If you look at the angle between the runway and the skid marks in the grass, it didn't just "edge" it's way off, it left the runway already misaligned with the center line by a pretty good angle.  

 

I don't claim to know any more than anyone else about what really happened, just playing back what seems plausible/credible from PPRUNE.

 

It's interesting to speculate but maybe we'll get some definitive info later.

 

John

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