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Emirates B777 gear collapse @ DXB?

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Emirates B777 gear collapse @ DXB?

Old 18th Sep 2016, 10:23
  #1621 (permalink)  
 
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Guys (girls?)

We're in danger of solving the wrong problem here!

What makes you think he wasn't able to hand fly the aeroplane? His middle names could be Chuck and Yeager, but even if he hand flew every single approach, how many times would he have had the opportunity to 'fly' a go-around after landing????

I bet there aren't many of us here that have done one for real. Hopefully we never have the requirement to. Fly a thousand manual approaches and it won't help you in this scenario one bit!

Knowledge and training (that means in the sim) is the only answer. Along with pre-briefing at moderately frequent intervals, such as when you operate to short runways, to at least keep the procedure fresh in your mind for when the requirement comes out of the blue, like here!

This pilot shouldn't have pushed the TOGA buttons on the ground AT ALL! If that's what happened, the chimp had instantly selected the WRONG motor program! He shouldn't have 'monitored' the thrust levers at all, he had to firewall them!

It's nothing to do with manual flying skills per se! It's about practicing THIS PARTICULAR MANOUVRE!

Solve other problems by all means. But they aren't what caused this accident!

The chimp is alive and well in every single one of us!! When we lived in caves he kept us alive. In a modern jet we need to watch him like a hawk!

Last edited by 4468; 18th Sep 2016 at 10:49.
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Old 18th Sep 2016, 10:50
  #1622 (permalink)  
 
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Aspects of human behaviour and training discussed in recent posts are like comparing a stone and a bird.
You can throw a stone with some confidence of where it will land, but when throwing a bird there is no control over the destination (a bird has human-like behaviour); where even with training and practice the best can deviate from the intention.
It is possible to make the bird more like a stone, clip its wings, bind it up, (procedures and practices), but then you loose the bird's ability to avoid hazards, especially those previously unseen en-route.
However, a bird might be encouraged to reach the desired destination by suitable placement of birdseed, change or add something to facilitate the desired behaviour.

In this accident an objective would be to apply and check GA thrust. Verification might better be achieved by looking at the engine instruments opposed to relying on feedback from moving thrust levers.
An alternative is to move the thrust levers as part of the GA switch, this also guides the eye to the thrust instruments; feed-forward guidance vice feedback.

Rigorous training and SOPs constrain pilots and will not guarantee appropriate behaviour in all situations, but with thought about the complexity of the task, time constraints, and workload, pilots can be helped to achieve the desired objective. Those who should consider these changes, regulator-manufacturer-operator, must have sufficient understanding of systems and integration - interaction, and the operational environment (professional culture, policies, procedures) in order to form an adequate judgement; they have to resolve complexity, redefine the task, simplify the manoeuvre, and in using their time wisely might benefit safety, perhaps reducing training costs as well.

The industry has to avoid being like a turkey, being cooped up in the office, single focus - overfed, and with little foresight, particularly about the days of the month - beware of, and learn from surprises.

Bird - Stone analogy from "The logic of failure" by D Dorner, ( English version) 1996, 'Recognising and avoiding error in complex situations'.

"... managers need to engage in deeper reflective thinking. This is particularly true about how they manage change. An understanding of systems thinking is necessary to succeed at this. "

http://c.ymcdn.com/sites/www.project...s/mayjun09.pdf

Last edited by alf5071h; 18th Sep 2016 at 16:31. Reason: Typo
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Old 18th Sep 2016, 10:57
  #1623 (permalink)  
 
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Some good thoughtful posts.

Given that windshear was present, it would have also been turbulent, and one thing that I have never seen addressed is our use of a only a single hand to fly when flying a complex manouver.

It is SOP to have one hand on the thrust levers and one on the yoke/side-stick on finals, but of course this means that only half of one's brain is being used to manipulate the attitude control of the aircraft. {The human brain is configured such that only the right side of the brain controls the left hand and vice-versa}. Add to this, the majority of people are right handed. So when a person flies from the left seat, as well as only using half their brain capacity, they are most likely to be using their non-dominant hand/brain side to operate the attitude controls in what can be a highly dynamic, quickly changing scenario. The other half of their hand/brain control capacity is simply static on the thrust levers.

I can imagine that given a turbulent approach, the Captain might have needed/wanted much finer control on the yoke and therefore having pressed TOGA, I wonder did he then take his right hand off the thrust levers and onto the yoke so all of his brain and both hands were being used to control the plane - trusting that the autothrust would do what he wanted? With moving thrust levers, there is perhaps less reliance given to monitoring the engine N1/EPR gauges, and so the lack of spool up might have been missed by both pilots?

If all this was the case it should have led to a much earlier go-around decision of course, but as I say, I have never seen this single handed business discussed.

(Obviously, one can only have one hand on a side-stick, but the FBW computers do at least assist the pilot, which mitigate this to some extent)

As many of us keep saying; the answer has to be better training.

We are always told how we must fly but one thing that might be beneficial might be to give us scenarios in the SIM that will deliberately lead to bad things happening? For example, landing on a short runway with a speed of +10kts leading to an over-run. The pilots would be told what was going to happen, and no jeapordy would be invoked, but it might be useful to actually experience the consequences of mis-handling. Otherwise, as long as we are there or thereabouts within the limits, we pass our SIM check and maybe never really appreciate what could happen if we went outside limits.

In the SIM recently I was given the scenario of AF447 - without being told it was going to happen, and the Captain was in on the plan, so he did/said nothing. To my absolute horror, I did pretty much the same thing as those AF pilots - (although I thought it was a Vaplha prot issue). Now obviously, I know the unreliable speed drill, but this was so subtle that I did not recognise it as such. Having had it demonstrated to me in that very dramatic way it will stay with me for ever and if I ever see that situation developing, I will know exactly what to do. (One thing that blocked my thinking was the very loud and persistent overspeed alarm, which drowned out the "stall stall stall")

My point is that any amount of words on a page about the incident and how to deal with unreliable speed etc, did not help me, but actually seeing and experiencing how subtle it can be and how it can go wrong first-hand has gone deep into my brain.
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Old 18th Sep 2016, 11:00
  #1624 (permalink)  
 
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I did a touch-and-go once with passengers on board (737). At 30 feet we got a windshear warning. Winds were gusty, and coming over a line of trees ajacent to the runway. So when we were below the tree line, a windshear warning was issued.

You did't read about it in the papers beacause I firewalled the engines. We very smoothly touched the runway, and off we went.

The most striking thing that I remember about this incident, was the absolute backbone instinct that drove me to firewall the thrust levers.

That was't the chimp in me. That was the fish ancestor trying to escape from danger.
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Old 18th Sep 2016, 13:12
  #1625 (permalink)  
 
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Originally Posted by 4468
It's nothing to do with manual flying skills per se! It's about practicing THIS PARTICULAR MANOUVRE!
I don't agree. Why do you think the FO called "speed"? Because he did what a current, practised pilot who is used to looking at his instruments for survival ie when handflying does. If one is well-versed in flying the aeroplane, even if one makes an almighty stuffup like hit the TOGA and not realise nothing happened because it was less than 5ft, he will shortly after notice the speed dropping off then instinctively work out there's no power.

I do agree that this particular manoeuvre has to be practised, but the fundamental underlying process/skill for any of our activities must be ability and currency on flying the aeroplane.
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Old 18th Sep 2016, 13:22
  #1626 (permalink)  
 
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The comment "chimp choosing wrong motor action in this scenario". Very valid. There was also a comment about 3 GA scenarios. The clue what do in which is in the small print read many moons ago, stored in the deepest longterm memory at the rear of the brain, and hopefully can be dragged forward in the split second it is needed years later. The standard SOP GA from Minima is in the current memory at the front of the brain, so no surprise this erroneous action was chosen.

The question was solutions.
1.Training, repetitive recurrency exposure: all good, but how often will it be used; how likely? Thus many HOT's would deem the time not best spent.
2. Make all GA's manual thrust = system redesign. Thus there is no choice & no doubt.
3. Change and re-enforce SOP's for PF to follow through TL's on any GA and for PM to verify as their priority. FCTM & company SOP's.

Every GA is the same motor action. No choice, no excisions, no doubts. JUST DO IT. 'Nike'.

Opinions?
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Old 18th Sep 2016, 13:47
  #1627 (permalink)  
 
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Every GA is the same motor action. No choice, no excisions, no doubts. JUST DO IT. 'Nike'.
I don't think they are. Take that 777 GA video from 12" off the ground (or did they touch down?) many pages back http://www.pprune.org/rumours-news/5...ml#post9476561. That is nowhere near a "normal" goaround: fly level with the ground/touchdown attitude at zot feet, with full power coming on, then gently rotate away so you don't bang the tail. That is not a motor action. An EGPWS escape is a motor action, processing a set of steps. This prang, I suspect, will be something that requires far more skill than a simple push n pull.

Last edited by Capn Bloggs; 18th Sep 2016 at 14:59.
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Old 18th Sep 2016, 16:27
  #1628 (permalink)  
 
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I tend to go with 4468. Lack of manual skill has nothing to do with this accident which was due lack of knowledge of automation. Since absence of thrust caused the problem everybody is forgetting that GO levers have another function, to give FD guidance for GA. If you execute all go rounds manually then the FDs remain in approach mode they need to be ignored. Not a good way to fly, on another day in poor visibility some one may go down following them (already happened thrice in airbus). GA procedure after touch down is an exception and should be treated as such. The only remedy for lack of knowledge is to learn, practice and revise during every briefing. If you brief the GA procedure after touch down the PM will make sure you do it.
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Old 18th Sep 2016, 16:46
  #1629 (permalink)  
 
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If you brief the GA procedure after touch down the PM will make sure you do it.
How much stuff are you ready to brief on the line ... ?
Far too much talking already.
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Old 18th Sep 2016, 17:16
  #1630 (permalink)  
 
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Bloggs: This prang, I suspect, will be something that requires far more skill than a simple push n pull.

Of course: we are in violent agreement.

Maybe I expressed myself badly. My intention was to suggest a discussion about whether the basic foundation of a GA should be the same, i.e. advance thrust manually (technically necessary) or follow the thrust levers to ensure movement (SOP). 4468 was discussing motor skills and muscle memory, and how it is possible to select the wrong one. I'm opening a discussion to remove that doubt. I know the pitch control is variable; that is piloting and a/c control; it is not thrust control. The root fault here seems to be lack of thrust. I'm looking at the root cause of why no thrust and considering simple options so it does't happen again.
Pushing TOGA causes an input into FD. That is pitch guidance. Let's separate pitch guidance & thrust application. On a B737NG, single channel ILS with AT, pushing TOGA disconnects AP but not AT; so PF needs to control pitch. However, all my previous airlines had PF SOP as following through on TL's. Does EK or Boeing have a follow through SOP, or is the SOP press & forget?
My question was regarding thrust, not a/c speed or pitch control: if every GA needed manual thrust, or follow through, would this type of confused accident happen again?
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Old 18th Sep 2016, 18:08
  #1631 (permalink)  
 
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I don't think that the issue in this case is as complex as some are indicating. You basically need two things immediately when performing a go-around - a positive pitch attitude (initially around 15 NU for this aircraft) & lots of thrust. This guy knew he needed those two things. He pitched the aircraft NU & 'called' for the power by pressing TOGA. What happened was an over-reliance on automation caused him to miss the fact that the automation had not delivered what he wanted. He wouldn't have got FD commands either, he was obviously used to setting a target pitch & going from there. Perhaps he was just starting to realize that he didn't have FD commands for the GA when it all started to go wrong.

He seems to me that he knew how to fly the required maneuver. He was just too trusting of the automation.
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Old 18th Sep 2016, 19:33
  #1632 (permalink)  
 
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He seems to me that he knew how to fly the required manoeuver. He was just too trusting of the automation.
No. He didn't know how to execute a go around after touch down. He wasn't too trusting the automation and was let down but expecting the automation to do something that it wasn't designed to do and was not going to happen. He needed to know that triggering go levers will neither get the thrust nor the FDs. Thrust had to be manually obtained and just sufficient rotation to avoid nose wheel touch down without FD guidance had to be obtained. 15 degrees would have caused a tail strike. There was no need to retract the gear before checking thrust. If gear was not retracted the aircraft may not have been destroyed.

Last edited by vilas; 18th Sep 2016 at 19:48.
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Old 18th Sep 2016, 19:36
  #1633 (permalink)  
 
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He pitched the aircraft NU & 'called' for the power by pressing TOGA.
For now, nothing to state in the report either TOGA switches has been pressed ...
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Old 18th Sep 2016, 20:20
  #1634 (permalink)  
 
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To me that is pretty key. The report neither says the pilots did or did not press TOGA. I guess we need the full report to appear, assuming that a press (that does nothing) if the wheels were grounded will be logged in the FDR. If they did press TOGA then we enter a world of the training/automation blame game, if not then it is a simple human error.

However is there a GA that doesn't require a whole boot full of thrust? And is there an aircraft in the world that doesn't respond to the throttles being jammed forwards - if so, why not make firewall the thrust the very first item on any go around, on any aircraft? It may be that the automatics on some aircraft will pull the throttles back since they still think they are landing, but at least if you forget you have that problem from 400 feet not 85.

Either that or a big red 'HAL get me outta here' mushroom button on the centre console to fly a pre set escape route... HAL does not forget to set thrust, retract flaps, avoid striking the tail, bring the gear up or miss the mountain. Of all the stages of flight where a machine should be able to do well, and where humans do badly due to high stress, this is a standout one.

Last edited by Snyggapa; 18th Sep 2016 at 22:15. Reason: Typo
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Old 18th Sep 2016, 21:01
  #1635 (permalink)  
 
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Well i'm looking forward to a few more G/A's in the Sim. That said, i can't help looking at this from a User Interface design question. There are myriad buttons & knobs within arms reach, but only 3 big chunky ones. Yoke/Le Sidestick & Thrust levers & Gear I suggest this is for a reason. The law of Primacy. This was a high workload incident, granted, with a tired crew, but those big levers should be high on the list of things to be all over. TOGA triggers et al are important, but "Go around-Set Thrust-Flaps-x" and push and hold the things forward, old school. A low energy state near the ground is not the time to be wondering 'what it's doing now...'
There but for the grace....

Last edited by neilki; 18th Sep 2016 at 21:02. Reason: witty autocorrect..
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Old 18th Sep 2016, 21:26
  #1636 (permalink)  
 
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if every GA needed manual thrust, or follow through, would this type of confused accident happen again?
"If every GA needed manual thrust", I suspect we'd just experience different types of accidents. In fact, likely more accidents, because we'd be changing the 99% of our GAs that are 'easy' and mostly work well, for the sake of the 1% of GAs that are badly described in the manuals, are hardly ever trained or briefed, but which will generally catch pilots by surprise!

More training of this manouvre, better manuals and knowledge, and regular pre-briefing are what's required to prevent this accident occurring again.

In fact, had they simply recently pre-briefed this manoeuvre, I could pretty much guarantee this accident would not have happened!

That's all.

Any other ideas are absolutely fine, but are simply solving problems that frankly, didn't occur here.

Last edited by 4468; 18th Sep 2016 at 21:40.
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Old 18th Sep 2016, 23:53
  #1637 (permalink)  
 
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Originally Posted by vilas
There was no need to retract the gear before checking thrust.
You don't check the thrust to retract LG, you confirm a sustained positive climb.
But you should check the thrust output before you rotate ...
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Old 19th Sep 2016, 06:07
  #1638 (permalink)  
 
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Sure! I am not linking the two but indicating wrong priorities. In a bounced landing GA there is no need to do anything other than thrust and attitude. Within two seconds flaps and gear was retracted indicates the crew wasn't treating this GA any differently. If briefing for this difference is not an option then perhaps following options can be considered:
1. Changing nothing because it didn't happen before and may not happen again.
2. Boeing activates the TOGA switches for all occasions and take chances if someone accidently triggers after landing or during flare.
3. Boeing deactivates TOGA auto throttle/FD mode for Go around and makes it a manual manoeuvre triggering even the FD GA mode at TOGA position.

From Airbus FCTM:

GO-AROUND NEAR THE GROUND


If the flight crew performs a go-around near the ground, they should take into account the

following:


‐ The PF should avoid excessive rotation rate, in order to prevent a tail strike.

- A temporary landing gear contact with the runway is acceptable.


In the case of bounce, the flight crew must consider delaying flap retraction


‐ The PF should order landing gear retraction when the aircraft reaches and maintains positive


climb with no possibility of subsequent touchdown..


I don't think it can be different in any aircraft

Last edited by vilas; 19th Sep 2016 at 06:37.
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Old 19th Sep 2016, 07:28
  #1639 (permalink)  
 
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Rat 5 @ 1636

"Make all GA's manual thrust = system redesign"
"Every GA is the same motor action. No choice, no excisions, no doubts. JUST DO IT."

You mean just as they were doing it on the DH121, AKA Trident over 50 years ago.
The Autopilot would fly the G/A from a DH of 12 ft. The activation of this mode was achieved by fully advancing the power levers manually.

I can't vouch for what would have happened if this was attempted after touchdown as in the 20 or so sim sessions I did I cannot recall this exercise. Nor for that matter on any other types I flew after that.

Is this or something similar that happens on the wonderbus? Power lever position or a TOGA button?
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Old 19th Sep 2016, 09:04
  #1640 (permalink)  
 
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TOGA on Airbus FBW can only be selected* by pushing the thrust levers fully forward. This is instinctive and logical.

Two big bad crashes have happened relatively recently to modern Boeings when the moving thrust levers did not move, and the crews apparently did not realise it and take appropriate action?

Perhaps the Airbus designers got it right after all when they made the thrust levers non-moving?


(*TOGA is automatically set if the aircraft slows into the Alpha prot region.)
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