Emirates B777 gear collapse @ DXB?
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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....
There but for the grace....
Last edited by neilki; 18th Sep 2016 at 21:02. Reason: witty autocorrect..
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Rat 5
"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.
if every GA needed manual thrust, or follow through, would this type of confused accident happen again?
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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Originally Posted by vilas
There was no need to retract the gear before checking thrust.
But you should check the thrust output before you rotate ...
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CONF iture
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
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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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?
"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?
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.)
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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I'm not going into details, just trying to have a discussion about avoiding mis-manipulation of a/c systems in stressful/startle scenarios.
It has been mentioned many time that one common screw up is an all engine GA. People have said that a manoeuvre brief will solve many problems. Hm? Briefing something you do rarely, 30mins before you might need to do it, is not a guarantee of success. It might help, but.......What can help is if the manoeuvre is simple and familiar to another common manoeuvre. This was the case with a normal GA & takeoff of B757/767. We executed both the same. Now, on B737 CL/NG I was astonished to discover that the GA is very different to takeoff: you accelerate during flap retraction via the flap lever. This is the only manoeuvre where this happens. I am still searching for a good reason why?
To make things worse there are some operators who emphasise that flap retraction must start at 400'. So they have the GA call, initial action of thrust, flaps, gear, roll mode all coming in very close succession, and then, just to increase the workload even more they have to accelerate the a/c and retract the flaps using a method they rarely practice. What's the rush, and why design the system to be so different to a normal takeoff?
Every other time we take off, be it normal or with engine failure, we accelerate at 1000'. A SE GA is 1000': in all cases the a/c is accelerated via MCP speed bug. Why make the all eng GA so different?
What happens on other Boeings? Is this now a common company technique? I realise this is not connected directly with DXB accident, but it does seem this can have human factors elements to the root cause.
On B737NG the AT disengages 2secs after touchdown. I assume this is 2secs WOW and not a bounce. It doesn't say if it's both wheels or one. On B737NG the only time you'd land with AT engaged is an autoland. It would be possible to still make a GA, but TL's would need to be pushed manually. In all my various Boeing airlines B575/676/737 the GA SOP was PF to follow through TL's and PM verify thrust, even on a GA with AT engaged. This would happen from an autopilot approach. The autopilot might disengage, or not, but AT 'should' advance to a suitable GA thrust. Perhaps because we flew more manual approaches, certainly in the latter stages, manual thrust was in our 'instincts & muscle memory'. It also improved, sharpened and widened our scan. We flew 1 handed on each control and were aware of the thrust setting.
I admit I had forgotten this performance, or lack of, of the AT after touchdown. It had never been trained nor experienced. However, because the technique was for PF to always follow through the TL's, just as on takeoff or any other GA, I would not expect it to have been a problem. Thrust would have been advanced.
I wonder if Boeing FBW AT pilots cover TL's or just trust, and only place hands on for TOGA selection? (I hear an AB GA is initiated by manually fire walling TL's, but do you cover them on approaches?)
I just wonder if this automated system is the best it can be, is a real safety improvement or needs tweaking.
It has been mentioned many time that one common screw up is an all engine GA. People have said that a manoeuvre brief will solve many problems. Hm? Briefing something you do rarely, 30mins before you might need to do it, is not a guarantee of success. It might help, but.......What can help is if the manoeuvre is simple and familiar to another common manoeuvre. This was the case with a normal GA & takeoff of B757/767. We executed both the same. Now, on B737 CL/NG I was astonished to discover that the GA is very different to takeoff: you accelerate during flap retraction via the flap lever. This is the only manoeuvre where this happens. I am still searching for a good reason why?
To make things worse there are some operators who emphasise that flap retraction must start at 400'. So they have the GA call, initial action of thrust, flaps, gear, roll mode all coming in very close succession, and then, just to increase the workload even more they have to accelerate the a/c and retract the flaps using a method they rarely practice. What's the rush, and why design the system to be so different to a normal takeoff?
Every other time we take off, be it normal or with engine failure, we accelerate at 1000'. A SE GA is 1000': in all cases the a/c is accelerated via MCP speed bug. Why make the all eng GA so different?
What happens on other Boeings? Is this now a common company technique? I realise this is not connected directly with DXB accident, but it does seem this can have human factors elements to the root cause.
On B737NG the AT disengages 2secs after touchdown. I assume this is 2secs WOW and not a bounce. It doesn't say if it's both wheels or one. On B737NG the only time you'd land with AT engaged is an autoland. It would be possible to still make a GA, but TL's would need to be pushed manually. In all my various Boeing airlines B575/676/737 the GA SOP was PF to follow through TL's and PM verify thrust, even on a GA with AT engaged. This would happen from an autopilot approach. The autopilot might disengage, or not, but AT 'should' advance to a suitable GA thrust. Perhaps because we flew more manual approaches, certainly in the latter stages, manual thrust was in our 'instincts & muscle memory'. It also improved, sharpened and widened our scan. We flew 1 handed on each control and were aware of the thrust setting.
I admit I had forgotten this performance, or lack of, of the AT after touchdown. It had never been trained nor experienced. However, because the technique was for PF to always follow through the TL's, just as on takeoff or any other GA, I would not expect it to have been a problem. Thrust would have been advanced.
I wonder if Boeing FBW AT pilots cover TL's or just trust, and only place hands on for TOGA selection? (I hear an AB GA is initiated by manually fire walling TL's, but do you cover them on approaches?)
I just wonder if this automated system is the best it can be, is a real safety improvement or needs tweaking.
Last edited by RAT 5; 19th Sep 2016 at 11:27.
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Vilas, you are right. It is no different in any aircraft. "PAFU" was a mnemonic drilled into us old boilers at basic flying training school. Power, Attitude, Flaps, Undercarriage. Even in liitle old Cessnas where the undercarriage was fixed, we still had to call it out. After CPL/IR and 200 hrs, I was one of the fortunate old school cadets that went straight into a heavy airliner. "PARFU" was the drill, again; "R" added for Radio in order to set the Flight system. It has worked for me in every aircraft and once, I bounced and decided to GA. PAFU had been well rehearsed, well practiced and on the day, proved to be a non-event. well, apart from Tea & biks with the Fleet Skipper who wanted to know why we bounced. Good grief. Biks were rubbish too.
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There are constant references on these posts to this being a 'bounced landing'. It wasn't. This was a decision to go around from a smooth but long landing. It was not the standard G/A, neither was it the standard 'bounce' that may have been previously practiced. This was a case of treating it like a touch and go but delaying the flaps until a safe rotation was made with sufficient thrust to safely climb away. The only concern would be ignoring the config warning as you climb away with landing flap, something the aircraft will happily do if done correctly.
No Airline can effectively teach for every possible scenario. They can, however, start by employing the best pilots and retain them by offering industry leading terms and conditions. You then recruit the best within this pool to become trainers who have enough experience and knowledge to encourage resilience and airmanship within a framework of robust SOPs, all the time being supported by a Company ethos that's not overly restrictive or prescriptive. It needs to be a genuine 'Just Culture' with effective support from Senior management, the CP's and their deputies.
Nobody for certain will ever know the reason why the Captain initiated a straightforward G/A procedure, other than the Captain himself. However, it would not take a genius to reason that many of the above mentioned factors may well have played a role, one way or another.
Harry
No Airline can effectively teach for every possible scenario. They can, however, start by employing the best pilots and retain them by offering industry leading terms and conditions. You then recruit the best within this pool to become trainers who have enough experience and knowledge to encourage resilience and airmanship within a framework of robust SOPs, all the time being supported by a Company ethos that's not overly restrictive or prescriptive. It needs to be a genuine 'Just Culture' with effective support from Senior management, the CP's and their deputies.
Nobody for certain will ever know the reason why the Captain initiated a straightforward G/A procedure, other than the Captain himself. However, it would not take a genius to reason that many of the above mentioned factors may well have played a role, one way or another.
Harry
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Good post Harry. Much to agree with.
Except:
You only get the config warning whilst on the ground. Once you're airborne, you are no longer 'taking off', and hence don't get the take off config warning.
As a point of interest, because you generally don't have much accelerating to do before reaching the bug and rotating, config warning only occurs for a very few seconds.
Except:
The only concern would be ignoring the config warning as you climb away with landing flap, something the aircraft will happily do if done correctly.
As a point of interest, because you generally don't have much accelerating to do before reaching the bug and rotating, config warning only occurs for a very few seconds.
1/ well in this case training is available for "rejected landings" after touchdown if the Airline Flight Ops Dept chose to do it. Ours does and has done for over 10 years. I last did it about 12 months ago in a Sim session in RJTT.
2/ Once you are Airborne the Config Flaps warning stops, then push TOGA and commence the SOP GO Around calls for your type.
2/ Once you are Airborne the Config Flaps warning stops, then push TOGA and commence the SOP GO Around calls for your type.
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Good post Harry.
I sure don't expect a guy at EK to answer, here, the following, but I can still ask :
I sure don't expect a guy at EK to answer, here, the following, but I can still ask :
- What happen to that crew if they disregard the audio caution and taxi to the gate ?
- How is it seen by the management to disconnect AP or AT ?
Smooth landing
One pilot witness was recorded as saying he watched that 777 do a very heavy landing and the crew went around from that heavy landing. That wasn't mentioned in the official initial report. But then again, it wouldn't be, would it? Local culture affects accident reports in some countries.
One pilot witness was recorded as saying he watched that 777 do a very heavy landing and the crew went around from that heavy landing. That wasn't mentioned in the official initial report. But then again, it wouldn't be, would it? Local culture affects accident reports in some countries.
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Possible thread drift but to be accurate there is one 777 config warning which is available when airborne (but only on GE-powered models), all others are inhibited after take-off.
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Smooth landing
One pilot witness was recorded as saying he watched that 777 do a very heavy landing and the crew went around from that heavy landing.
One pilot witness was recorded as saying he watched that 777 do a very heavy landing and the crew went around from that heavy landing.
This crash (thankfully no body bags, nice job on the evac) seems to hinge upon three core elements:
1. Decision to go around (SOP based or condition based?) - possible "supervisory error" finding
2. Go around actions taken (pitch and power?) - possible "training/CRM" finding
3. Decision to raise gear (when?) - possible "training/CRM" finding.
Some comments regarding corporate culture and their influence (sometimes insidious) have been made here, but whether or not the final report addresses that remains to be seen.
Someone pointed out earlier that had the plane settled with the mains still down, there may still have been some damage to the aircraft (due to a firmer landing/thump) but significantly less damage than with the landing gear up and the aircraft sliding down the pavement. (For example, less likely that engine integrity / mount being compromised ... fire ... )
1. Decision to go around (SOP based or condition based?) - possible "supervisory error" finding
2. Go around actions taken (pitch and power?) - possible "training/CRM" finding
3. Decision to raise gear (when?) - possible "training/CRM" finding.
Some comments regarding corporate culture and their influence (sometimes insidious) have been made here, but whether or not the final report addresses that remains to be seen.
Someone pointed out earlier that had the plane settled with the mains still down, there may still have been some damage to the aircraft (due to a firmer landing/thump) but significantly less damage than with the landing gear up and the aircraft sliding down the pavement. (For example, less likely that engine integrity / mount being compromised ... fire ... )
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wonder if Boeing FBW AT pilots cover TL's or just trust, and only place hands on for TOGA selection? (I hear an AB GA is initiated by manually fire walling TL's, but do you cover them on approaches?)