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Emirates B777 gear collapse @ DXB?

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Emirates B777 gear collapse @ DXB?

Old 9th Aug 2016, 16:51
  #701 (permalink)  
 
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Assumptions

Wirb, #702 "Flaws that we can train out ..."
This is a gross assumption considering all of the challenges in modern aviation.
James Reason provides a more balanced view, in that the "human condition is difficult to change, but changing the working conditions can be more effective and often easier".
In particular by avoiding opportunity for combination of factors, e.g. its difficult to 'train out' a bounced landing, but the thrust control system could be improved to cover a greater range of situations with the same procedure.
The principle is to reduce complexity, aid consistency, and thence reduce training and documentation costs. Aim to reduce the need for the the human to detect and differentiate between situations or remember alternative procedures.

Similarly, in your #680; whereas technology should reduced workload you resort to workarounds to counter system deficiencies, introduce additional checks (FMA SOPs), place greater demands on human attentional resources, and thus with higher workload challenge the human ability (time) to appreciate what the aircraft altitude, speed, and thrust levels are.
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Old 9th Aug 2016, 16:58
  #702 (permalink)  
 
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@safetypee: as usual, you offer excellent insights.

Back to the basics of attitude flying and the old saw of pitch plus power equals performance. (Long running theme in the AF 447 accident discussion).

If the pilot flying the aircraft controls pitch and power (and correct wing attitude) he / she has set the conditions for what comes next. The pilot monitoring/co-pilot assists with the plethora of other tasks that take more hands, and require checklist, trigger the challenge reply chains, etc.

Has the system, in trying to reduce workload, cluttered up task management in a critical phase of flight? (Landing is a critical phase of flight).
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Old 9th Aug 2016, 17:12
  #703 (permalink)  
 
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safetypee,

I perfectly understand your reasoning it's just that the implementation sometimes isn't as straight forward as the engineering, both hardware and software, would want it to be.

reduce complexity, aid consistency
Unfortunately this scenario has resulted in highly complex machines with a vast plethora of integrated systems which all rely upon each other with varying degrees of redundancy to mitigate for the inadequacies of the human mind.

As Tesla have demonstrated, where both the cars automated systems and the driver failed to detect a scenario which hadn't been anticipated by either the software designers or the hardware designers, the result was the loss of the drivers life. I am aware that Tesla state that the automation is in Beta but seriously? How far do we let the automation go?

Aircraft are seriously complex pieces of machinery. I like simplicity, it makes my day to day life easier and enables me to fly the sometimes ludicrous duty times I fly. However the increased tendency to 'hide' complexity and system cross over from the operating crew has a darker side. If the technical knowledge isn't there as to the cascade effect that a singular system failure might precipitate then the workload on the flight crew at a time of high stress will also increase. Complex systems presenting simple information should never replace the innate ability of those designated to 'fly' the machine from performing their job. We are rapidly approaching a point where the systems cascade of multiple failures or, even in the case of a single failure (AF), might cause sensory and capacity overload in under trained and overwhelmed crews.

The reason we have SOP's is simply to allow people who often have never flown before together to be able to work as a team and to realistically expect to get a standardised product from your colleague. Irrespective of what seat they might occupy.

Ironically the FMA purely supplies the information to the pilot as to exactly what mode the Autopilot system is in thus ensuring that the modes you've selected on the MCP are the actual modes the A/P is giving you! It's not an additional check more of an affirmation.

As the previous couple of posts here have alluded to the question here is WHY did the aircraft not climb adequately after what should have been a routine manoeuvre albeit with ground contact. Was there a failure of the A/T system? Did the engines fail to spool due to an EEC fault/logic problem or, more simply, did the crew fail to remember that the TOGA switches are inhibited after touchdown? A simple check of the FMA by the NHP would have seen that the A/T system was not in TOGA in that case.

So whilst I agree that simplicity is best we simply cannot ignore that we must train the next generation of pilots to understand that it is an aeroplane and as such they must also understand that occasionally it might need to be flown like one without the bells and whistles.
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Old 9th Aug 2016, 17:19
  #704 (permalink)  
 
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Reading, understanding, and knowing what you want on the FMA would fix most problems.
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Old 9th Aug 2016, 17:36
  #705 (permalink)  
 
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Read Mr. Bailey's article with interest. He present a compelling argument for the confusion may have happened (or not) when the PF initiated the TOGA using the switch. But I didn't see where he explained why the PNF (apparently mistakenly) thought the aircraft had achieved the positive rate of climb necessary before retracting the landing gear, or why, even if it he thought it had, he didn't leave the gear down as Boeing recommends for a TOGA after a bounced landing.
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Old 9th Aug 2016, 17:39
  #706 (permalink)  
 
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But I didn't see where he explained why the PNF (apparently mistakenly) thought the aircraft had achieved the positive rate of climb necessary before retracting the landing gear
Cognitive failure? Close to the ground so thought it was a standard 'take-off' perhaps? Selected Gear instead of Flaps? They've all happened before. The FDR will clear most of it up along with the crew accounts.
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Old 9th Aug 2016, 18:25
  #707 (permalink)  
 
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Wow! So many rumours!

This thread is going all over the place. We have contradictory evidence from those supposedly in the know.

Wheels down, wheels up. Bounced or didnt bounce? How can we tell? (except perhaps by listening to pax testimony?)

Impossible to call with so much conflicting info...
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Old 9th Aug 2016, 18:25
  #708 (permalink)  
 
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Originally Posted by Mark in CA View Post
Read Mr. Bailey's article with interest. He present a compelling argument for the confusion may have happened (or not) when the PF initiated the TOGA using the switch. But I didn't see where he explained why the PNF (apparently mistakenly) thought the aircraft had achieved the positive rate of climb necessary before retracting the landing gear, or why, even if it he thought it had, he didn't leave the gear down as Boeing recommends for a TOGA after a bounced landing.
Just as pilots shouldn't "rely" on automatics, but rather use them in a "Trust, but verify" manner at an appropriate level depending on the regime or maneuver, this mantra also holds true for working as a crew. A PF's command to raise the gear after a PNF/PM's "Pos Climb" callout should only be given after PF also verifies the pos climb and therefore the callout is appropriate. I'd be shocked if EK's SOPs left only one pilot in a loopless, monitoring/decision-making/action process for a configuration change, pushing blind reliance on him/her by the other during a critical phase of flight.

Since my assumption is that EK SOPs provide for gear-retraction as a 2 pilot-looped operation, a cognitive breakdown/mistake on the part of one, whether PF or PNF/PM, is expected to be picked up by the other via verification before any action takes place. This is fundamental and has nothing to do with the intricacies of automatics peculiar to specific aircraft, but has everything to do with with a mindset of "reliance". Because humans are fallible, blind reliance on another human w/o verifying leads down the road to merely parroting a script of commands at certain triggers regardless of reality and, in the wrong set of circumstances, outside every pilot's prime directive to always fly the aircraft.

Reliance on automatics due to their complications and/or peculiar gotchas get a lot of bandwidth, deservedly so, but it shouldn't be forgotten that countering the root...a propensity to lapse into a mindset of reliance (which is a lapse in SA) itself...has a broader application that helps maintain vigilance across the spectrum to include fallible humans as well.

Last edited by PukinDog; 9th Aug 2016 at 19:11.
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Old 9th Aug 2016, 18:32
  #709 (permalink)  
 
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Who to believe?

Originally Posted by PukinDog View Post
Just as pilots shouldn't "rely" on automatics but use them in a "Trust, but verify" manner at an appropriate level depending on the regime or maneuver, this mantra also holds true for working as a crew. The PF command to raise the gear after a PNF/PM's "Pos Climb" callout should only be given after PF also verifies the pos climb and therefore the callout is correct. I'd be shocked if EK's SOPs left only one pilot in loopless monitoring/decision-making/action process for a configuration change.
Ironically, one (inside) post claims positive rate of climb (for a while) and wheels left down. The latter being a boon, apparently

This is one case where I think sitting and waiting for the facts might be the best tactic...
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Old 9th Aug 2016, 18:33
  #710 (permalink)  
 
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Wheels down, wheels up. Bounced or didnt bounce? How can we tell? (except perhaps by listening to pax testimony?)

Impossible to call with so much conflicting info.
Because it's speculation as to a possible cause not a 'call' as the actual information from what caused the crash hasn't been made public yet. It would be inappropriate to attempt to discuss 'definitives' when they don't exist and in poor regard to the operating crew.
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Old 9th Aug 2016, 18:41
  #711 (permalink)  
 
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If the aircraft reached 150 feet in the bounce and the attempted goaround then the PNF was probably justified in calling "positive rate". One of the characteristics of the 777 is that although the landing flare is done with only one hand the rotate and goaround manoeuvre is done with both hands. Anyone who has seen lots of go-arounds on a 777 simulator will note the handling pilot gives a quick push on the TOGA switches and then pulls up to 15 degrees using both hands and looks at the PFD. The thrust levers then (should) go forward on their own. In the olden days the good old flight engineer made sure they did. These days the P2 very rarely backs them up. In the accident situation the non handling pilot was probably bringing the flap in to 20 and calling positive climb and raising the gear and then looking for the FMA indications and then wondering what was happening. Pitch and power saves the day however looking for and calling out the FMAs uses up valuable time, especially if you have not got the FMAs you are expecting (Thrust Toga Toga) The Asiana accident and now probably this one involved manual flying and an expectation of autothrottle to provide the required thrust.
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Old 9th Aug 2016, 18:54
  #712 (permalink)  
 
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Originally Posted by suninmyeyes View Post
If the aircraft reached 150 feet in the bounce and the attempted goaround then the PNF was probably justified in calling "positive rate".

I'd be hard pressed to believe that any landing could result in a 150 ft. bounce. Such a landing would probably result in collapsed landing gear and a severely buckled fuselage.
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Old 9th Aug 2016, 19:18
  #713 (permalink)  
 
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This is a very interesting incident in that it is (on first blush only) nearly identical to the Asiana incident at SFO. If the current hypothesis (that the crew went around and expected the AT to spool up the engines, when in fact they hadn't engaged TOGA for whatever reasons) then it is a fact that the evolution of both incidents was pretty much identical: Crew makes large pitch change that requires excess thrust to compensate for and expects AT to react accordingly, and within a few seconds things fall apart as the aircraft sheds airspeed because there was no corresponding increase in thrust.

And in both cases the failure to monitor the throttles happened in the final phase of landing, and in both cases it happened when things were not as expected. (Asiana was not stabilized and was high and hot for way too long, EK 521 appears to have bounced the landing for whatever reasons...) But in any case this would represent the second time in several years that a 777 was a total loss due to the crew failing to properly manage the AT in a critical phase of the landing process.

It could be a training failure, it could be a programming failure, it could be both, or it could be something else, but what I am seeing here is a specific problem with (at least) the 777 series, one that Boeing and regulators need to recognize, acknowledge, and work to ameliorate.

This is obviously all speculative at this point, but the similarities are surprisingly close, as is the outcome- it will be interesting to see if these two incidents result in a major phase or process shift in either training or operations, and/or in the programming of the machine itself.

Cheers,
dce
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Old 9th Aug 2016, 19:48
  #714 (permalink)  
 
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Originally Posted by wonkazoo View Post
This is a very interesting incident in that it is (on first blush only) nearly identical to the Asiana incident at SFO.
In that it involved a 777, yes. Beyond that ... really?
  1. This crew didn't get 37 knots slow on final.
  2. The weather as reported was less benign than the SFO event.
  3. Operating philosophy similarities between the two airlines? Give that some time get sorted out.
Are you sure you want to take the "blame the machine" line, per your last paragraph? Seems premature. (A malfunction may have occurred that has yet to come to light ...)
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Old 9th Aug 2016, 19:56
  #715 (permalink)  
 
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I'd be hard pressed to believe that any landing could result in a 150 ft. bounce.
I was thinking about this accident flying back across the pond this morning.

It appears there were some GAs by other aircraft prior to the event itself. A tailwind on approach turning to a headwind on landing is a positive shear and leads to increasing IAS, the auto throttle reducing power and a tendency to get high and/or float.

If a GA was initiated due to instability or landing deep, the IAS might have been quite high, so if you went to a GA pitch attitude, there might indeed be c.150’ worth of climb there (triggering a "positive rate") even with the engines at approach idle. After that the speed would wash off and the aircraft sink back towards the runway. If the pitch was raised further approaching the deck you’d get a bit of cushioning from going back into ground effect and a tail strike near the stalling angle...
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Old 9th Aug 2016, 20:26
  #716 (permalink)  
 
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Errmmm...

Originally Posted by suninmyeyes View Post
If the aircraft reached 150 feet in the bounce and the attempted goaround then the PNF was probably justified in calling "positive rate". One of the characteristics of the 777 is that although the landing flare is done with only one hand the rotate and goaround manoeuvre is done with both hands. Anyone who has seen lots of go-arounds on a 777 simulator will note the handling pilot gives a quick push on the TOGA switches and then pulls up to 15 degrees using both hands and looks at the PFD. The thrust levers then (should) go forward on their own. In the olden days the good old flight engineer made sure they did. These days the P2 very rarely backs them up. In the accident situation the non handling pilot was probably bringing the flap in to 20 and calling positive climb and raising the gear and then looking for the FMA indications and then wondering what was happening. Pitch and power saves the day however looking for and calling out the FMAs uses up valuable time, especially if you have not got the FMAs you are expecting (Thrust Toga Toga) The Asiana accident and now probably this one involved manual flying and an expectation of autothrottle to provide the required thrust.
I don't think anyone said they bounced 150 ft. If that source is valid, one has to assume the climbed there albeit briefly. Without bouncing.

The same source claims the wheels were down. That doesn't really add up looking at the wreckage.

But a toga at low level (bounce) and pitch up 15 degrees is likely to end in a tail strike. SOP at low level is toga thrust and maintain 5 degrees till you are out of there.

Another source says they bounced, tried a GA and failed (with wheels up, or on their way up).

So who to believe?

Hard landing (WS), bounced, wheels up and messed up the GA. Or no landing (WS?), and messed up the go around (wheels still down).

Without knowing what happened for sure, it seems churlish to speculate. Too much conflicting information from "inside sources" that we second guess the wrong scenario.

That said, we can take some lessons (even from erroneous scenarios).

If you push toga, make sure that you have toga. And if you bounced before you call GA, leave the wheels down.
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Old 9th Aug 2016, 21:09
  #717 (permalink)  
 
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This might have helped but....

Might not be news to others but I only recently discovered that if you run LiveATC with Flightradar you can see approximately where the transmissions to and from the aircraft are made. Tried the same thing with archived outputs including 521 crash only to find that Flightradar plays back at X 12 so cannot be matched to ATC. If anyone else wants to investigate further, today is probably the last day you can replay 3rd august on Flightradar.
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Old 9th Aug 2016, 22:15
  #718 (permalink)  
 
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Originally Posted by suninmyeyes View Post
If the aircraft reached 150 feet in the bounce and the attempted goaround then the PNF was probably justified in calling "positive rate". One of the characteristics of the 777 is that although the landing flare is done with only one hand the rotate and goaround manoeuvre is done with both hands. Anyone who has seen lots of go-arounds on a 777 simulator will note the handling pilot gives a quick push on the TOGA switches and then pulls up to 15 degrees using both hands and looks at the PFD. The thrust levers then (should) go forward on their own. In the olden days the good old flight engineer made sure they did. These days the P2 very rarely backs them up. In the accident situation the non handling pilot was probably bringing the flap in to 20 and calling positive climb and raising the gear and then looking for the FMA indications and then wondering what was happening. Pitch and power saves the day however looking for and calling out the FMAs uses up valuable time, especially if you have not got the FMAs you are expecting (Thrust Toga Toga) The Asiana accident and now probably this one involved manual flying and an expectation of autothrottle to provide the required thrust.
A quick push of a toga button then a pull on the yoke with both hands while focusing on pitch w/o any visual verification or confirmation by either pilot using the engine readouts that GA thrust is being produced is a major breakdown in fundamentals. No engine performance = no climb performance. It would be like not checking T/O power while taking off, and I believe most SOPs call for doing the same during a GA. FMAs and auto-settings to go up, up and away are rendered meaningless without it so ensuring/confirming thrust is being developed/increasing is as high a priority as pitching up. Pitch up without thrust, you're boned. The prospect that thrust verification by engine readouts during a GA wouldn't be incorporated and prioritized, or if auto is lost both pilots not recognizing and reverting to manual means to achieve it, is disconcerting.
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Old 9th Aug 2016, 23:37
  #719 (permalink)  
 
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Wouldn't the failure of the thrust levers to move under the PF's hand when TOGA was selected have provided instant feedback?
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Old 9th Aug 2016, 23:48
  #720 (permalink)  
 
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Wouldn't the failure of the thrust levers to move under the PF's hand when TOGA was selected have provided instant feedback?
Only if he actually had his hand on the thrust levers. I see too many pilots think they need two hands on the control wheel.
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