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Smartlynx A320 runway excursion EETN 28.2.2018

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Smartlynx A320 runway excursion EETN 28.2.2018

Old 20th Mar 2018, 07:39
  #81 (permalink)  
 
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And if we continue the train of thought and suppose that the trainee for some reason (seizure!) accidentally pushed and held the takeover button on their stick - or that their sidestick suffered a malfunction such that their takeover button became permanently pressed - then even in such a case the TRE's sidestick would regain priority once the TRE pushed their 'takeover' button, as the last discrete button press (by which specifically we mean a transition from unpressed to pressed, not a continuation of the pressed state) assigns priority.

Thusly a wedged/locked sidestick with a wedged/locked priority button is still overridden with any single press of the priority button on the other stick at any later point in time.

What could not be overridden, I believe, would be 'rapidfire' of the priority button on the trainee's side.

I could only see that type of input happening - in the remotest of chances - if the relevant wires to the button had become loose or fractured and were intermittently making and breaking contact as the wire moved.

I suspect also this can be ruled out as I would imagine that the sidestick buttons are double-pole-changeover type, with a button press simultaneously closing one circuit and opening another? I imagine this knowing that even the brake pedal interlock switches on economy cars work this way. But I do not know for sure!
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Old 20th Mar 2018, 08:42
  #82 (permalink)  
 
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For me this looks like a much, much simpler scenario. And it did happen before.
If you do not apply full thrust for the go-around (and you do not need this for an empty aircraft on training flights) you do not trigger the TOGA logic, your autopilot still tries to land the aircraft.
"the aircraft suddenly failed to respond to any inputs and shortly afterwards both engines lost power" This is what you expect from an active autopilot which you ask to land the aircraft...
Computers do not do what you want them to do, but what you ask them to do... Learn the language of the computer if you want to use it. To initiate a go-around you have to advance the throttles all the way to the TOGA detent. If you don´t, your aircraft behaves strangely and won´t go around the way you want it to.
This accident is probably the same issue as the 777 in Dubai, just on a different type of aircraft and hence a different type of fingertrouble initiating a go-around (or not initiating it...).
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Old 20th Mar 2018, 09:01
  #83 (permalink)  

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^^^ rubbish
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Old 20th Mar 2018, 09:09
  #84 (permalink)  
 
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https://flightsafety.org/wp-content/...y-First-23.pdf
https://www.atsb.gov.au/media/793232/ao2007044.pdf
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Old 20th Mar 2018, 10:59
  #85 (permalink)  
 
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Not sure about the logic of that 'simpler' scenario... autopilot trying to fly the plane on a takeoff roll? That would mean autopilot engaged on the ground before takeoff? I'm pretty sure they don't do autolands during the basetraining so I see no logical reason why the autopilot would have any kind of control during a touch & go...

And the first part of the thrust lever movement is still direct control in the Airbus, correct? So even if you don't move them all the way to the TOGA detent, you should still get a bunch of thrust. Perhaps the logic doesn't change but there shouldn't be any autopilot engaged sooo....

But I don't fly the Airbus so maybe I lack some knowledge there. Your simpler scenario just doesn't make any sense to me, perhaps my type is too simple . The two PDFs you linked also don't really seem relevant as they treat go-arounds performed during the approach and from autopilot engaged situations.
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Old 20th Mar 2018, 12:27
  #86 (permalink)  
 
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@intrance

could still influence the FD bars right?

so yes they would gain speed in the MCT setting as ATHR becomes inactive but if they go back to the CLB detent the ATHR kicks back in (see the second pdf and scroll to the nice diagram).

a trainee flying the FD bars could then produce the strange behaviour of the plane not wanting to climb. dual input would sound as described but maybe it wasn't recognized properly as described in other posts.

and as for the second pdf:
the PIC had more than enough thrust and speed to climb but he didn't. (in the diagram you can see the airspeed being quite high and they are still descending)
so even as he was controlling the aircraft he was probably following the FD.

even the training captain taking control might have fallen for this stuff even if he shouldn't have.

too bad FDR data is not just made public at the start of the investigation now that would reduce the speculation on defects and human factor not what actually happened
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Old 20th Mar 2018, 13:31
  #87 (permalink)  
 
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Originally Posted by wiedehopf View Post
too bad FDR data is not just made public at the start of the investigation now that would reduce the speculation on defects and human factor not what actually happened
It always seems ghoulish and disrespectful to the dead to speculate too wildly about human failures, mistakes and suchlike in an incident which claims lives, especially the lives of the flight deck crew.

In a bloodless incident like this I quite enjoy the chance to harmlessly speculate, bounce scenarios off people and learn some systems knowledge.
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Old 20th Mar 2018, 13:37
  #88 (permalink)  
 
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If you have just made a successful landing in the A320, and you don't set proper TOGA power, what mode does the automation revert to? What will the FD show? Will it be approach mode and basically only show a localizer perhaps? I'd doubt anyone will try to fly a FD with the vertical guidance showing level or just completely missing for a takeoff roll...

The scenario just sounds like a bit of a reach honestly. But who knows. I'd still put my money on some sort of technical issue or perhaps the dual input issue.
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Old 20th Mar 2018, 19:43
  #89 (permalink)  

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Volume, thank you for the links, my favourite would be this one: https://www.bea.aero/docspa/2012/f-z...f-zu120313.pdf.

Neither of the three has any relevance to the situation in Tallin, I believe. Sorry for my brevity in the morning. The bolded text below is yours.

If you do not apply full thrust for the go-around It is was not a go-around, but a touch-and-go. In the context a seriously different thing.

an empty aircraft on training flights standard base-training load as per Airbus training manual is +10t ballast, not empty

full thrust for the go-around (and you do not need this You're starting the "-and-go" part of the show after some essential re-configuration from around 90 kts. with maybe no more than 900 mtrs left. The only way to reasonably assure T/O perf is to go full TOGA, no middle ground.

not trigger the TOGA logic, your autopilot still tries to land the aircraft no, it was not engaged for the preceding landing.

"the aircraft suddenly failed to respond to any inputs and shortly afterwards both engines lost power" This is what you expect from an active autopilot which you ask to land the aircraft... Without attacking the quote's accuracy - which may be prudent later: not on Airbus. To make an input is to pull, and pull on the stick disengages the A/P. I am not saying the aircraft remained responsive, but if tragically so then it was not a result of A/P engaged.

Also there would be no leftover flight directors.

Last edited by FlightDetent; 20th Mar 2018 at 21:28.
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Old 20th Mar 2018, 19:49
  #90 (permalink)  

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Originally Posted by Intrance View Post
successful landing in the A320, and you don't set proper TOGA power, what mode does the automation revert to? What will the FD show?
Nothing engaged, nothing armed. Empty.
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Old 20th Mar 2018, 20:37
  #91 (permalink)  
 
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If the AC had remained in Flare mode a pitch down order would be introduced and the behaviour and feel of the flight controls would be very different to what a trainee would be used to. Any release of the side stick, before flight mode has resumed, would mean an immediate pitch down. This would be compounded if the attitude at 50`on the approach was very nose down, as that is the reference point the system uses for the flare manoeuvre.

An unstable approach path with a steep nose down attitude crossing 50´followed by a hard landing with a failure of the air ground sensing logic would have prevent the aircraft flight control laws transitioning to ground mode. At "rotate" the trainee would have pulled the side stick to start the rotation, if he then released the pitch input on the side stick (as in a normal T/O) the aircraft would have pitched down and maybe made contact with the runway. If we combine this with an over-keen "positive climb - gear up" call the aircraft might have contacted the runway with the gear in transit. Leading to damage of the gear doors and engine contact with the ground.
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Old 20th Mar 2018, 20:48
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If there had been a technical problem Airbus would have issued a notice to operators by now.Has anybody heard of one being issued?
The last time I did base training in the aircraft the brief was after touchdown the trainer would reconfigure the aircraft, whilst the trainee kept it straight. Once this had occurred the call was to stand the thrust up , and when stable apply TOGA thrust. Did the trainee not apply Toga before the end of the runway?

Last edited by tubby linton; 20th Mar 2018 at 22:01.
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Old 21st Mar 2018, 09:20
  #93 (permalink)  
 
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Did the trainee not apply Toga before the end of the runway?
That´s what I suspect.
And this would not be a "technical problem", but mishandling of the aircraft. Airbus did issue several publications to clarify the use of the throttles and the TOGA logic if no full power is required.

It is was not a go-around, but a touch-and-go.
Is it yet clear, how much it really touched? It may have kissed the ground, but not enough to trigger the ground logic. Excessive speed was mentioned in the reports.
The FDR will tell.
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Old 21st Mar 2018, 10:34
  #94 (permalink)  
 
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Originally Posted by tubby linton View Post
If there had been a technical problem Airbus would have issued a notice to operators by now.Has anybody heard of one being issued?
The last time I did base training in the aircraft the brief was after touchdown the trainer would reconfigure the aircraft, whilst the trainee kept it straight. Once this had occurred the call was to stand the thrust up , and when stable apply TOGA thrust. Did the trainee not apply Toga before the end of the runway?
That's how we do it. Is it possible that the trainer got distracted and they tried to get airborne with the TL's just stood up? Hard to believe as CM1 should have put their hands on the TL's for the remainder of the take off run and someone should have been reading the FMA. Even if the TL's were only pushed to CL detent I would have thought there would be enough power to get the thing airborne in an empty aeroplane, but I guess that if they were not and the thing was struggling to launch an early Gear Up could have squatted it back down on to the moving gear. Going to be a fascinating story when it all come out.
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Old 21st Mar 2018, 10:55
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Many moons ago I witnessed a 73' do a derated takeoff with a slight (1-2 kts) tailwind component. FO instinctively selected gear up as soon as mains left the ground, just as a slight increase in tailwind caused the aircaft to slowly sink. Full thrust was applied but with the time lag the plane settled back on the runway with gears retracted, sliding on the engine pods and the rear fuselage for a few seconds until it climbed away. Crew were unaware of the ground strike and continued takeoff, ony to return after the aircraft failed to pressurize. Interestingly the engine pods had minimal damage (with no damage to the engines themselves) but the fuselage needed extensive repairs.
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Old 21st Mar 2018, 21:33
  #96 (permalink)  

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macdo / tubby: the airbus drill is bit different. Stand up first, then conf change followed by TOGA. (checked the book right now).

Volume: the problematics explained so well is PLENTY of power, but automatics / guidance still aimed to land. Does not apply here. Their automatics were off by the nature of the landing done, but not enough thrust... The "touch-and-go" is "land, then roll quite a bit, and takeoff": no way to fool WoW there. (red herring anyway)
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Old 21st Mar 2018, 22:17
  #97 (permalink)  
 
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Do you have a reference Flightdetent?
We always did it as I described , and recounted here.
https://assets.publishing.service.go...OZBY_07-14.pdf
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Old 21st Mar 2018, 22:42
  #98 (permalink)  

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These are leaked into public domain (noted: yours is more recent - useful read BTW!)

http://elearning.onurair.com.tr/webc.../BSTR_A320.pdf
http://cbt.brusselsairlines.com/webc...E-TRAINING.pdf
https://www.cockpitseeker.com/wp-con.../fctp/fctp.pdf
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Old 23rd Mar 2018, 07:54
  #99 (permalink)  
 
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If the thrust levers had been stood up but then not advanced to TOGA it would likely have produced the flight path that occurred. But can anyone suggest a technical failure or failures which would fit in with what the operator has said happened?
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Old 27th Mar 2018, 06:15
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What about the possibility of a double ELAC failure at the wrong time and side sticks U/S?
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