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Emirates B777 gear collapse @ DXB?

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Emirates B777 gear collapse @ DXB?

Old 9th Aug 2016, 00:59
  #641 (permalink)  
 
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It is the result of the imperfect interaction of the pilots with supposedly failsafe automatics, which pilots are rigorously trained to trust, which in this case failed them
The problem is, the 777 autothrottle was never designed or intended to be a 'failsafe' system. It was not certified as flight critical because the pilot can always override what it's doing simply by manually moving the thrust levers. Plus, unlike most flight critical systems, there is an "ON/OFF" switch. If pilots are being taught otherwise, you've just identified a big part of the problem.
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Old 9th Aug 2016, 01:08
  #642 (permalink)  
 
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Mr Bailey's analysis sounds correct, although he has simplified it for his audience. Hence his statement that pilots are "rigorously trained to trust failsafe automatics".
It would be more accurate to say repeated experience reinforces expectation of a certain result from a given action, and in an unusual and stressful event the inevitable intuitive reaction may end up with a situation nobody expected.

We can bang on about pushing the thrust levers up as an associated action, and fair enough, but strictly speaking thats not how the system is designed, and not how we use TOGA on a day to day basis. Off the top of my head the only procedures formally trained that way are Windshear and GPWS. I have never heard of go round off a bounce being trained for either.

And who knows, maybe the thrust levers were shoved forward but not far enough? In fact that sounds quite feasable: an armful of power lever and expecting the autothrottle to finish it off would disguise the situation.

It has become common practice to brief the FCTM procedure for bounced landing in the last few years. I have never heard any body say "oh, and by the way: Autothrottle TOGA mode won't work". That would be because nobody has thought of it before. Same as prior to the Asiana crash nobody had thought about the effect of indirect mode change. And half of all pilots still don't understand it.

This thread will probably spin off into a manual skills blag but that would be missing the point. And the point is the Boeing FCTM, FCOM and training.

Of course all this is still just speculation in the absence of facts.

Last edited by HPSOV L; 9th Aug 2016 at 01:40.
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Old 9th Aug 2016, 01:39
  #643 (permalink)  
 
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Not necessarily true

"It has become common practice to brief the FCTM procedure for bounced landing in the last few years. I have never heard any body say "oh, and by the way: Autothrottle TOGA mode won't work". That would be because nobody has thought of it before. Same as prior to the Asiana crash nobody had thought about the effect of indirect mode change. And half of all pilots still don't understand it."

Actually, my company teaches press TOGA, push throttles and keep pressing TOGA until it engages. We teach this precisely because GA will not engage if the squat switches are on.
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Old 9th Aug 2016, 01:55
  #644 (permalink)  
 
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And half of all pilots still don't understand it.

The point is that they don't have to understand it - as long as they do not give full control to it & continue to fly the aircraft. Once you abdicate your responsibility as a pilot to fly the aircraft & give it to the automatics, you are starting down a very slippery slope.


Fully understanding the automatic systems on an aircraft is desirable & everyone should spend time on this throughout their career, but with the complexity of systems these days & the lack of currency with some of the more unique & subtle areas of automation, no one can know or remember everything. That is why you should never give full control to the automatics. You should always be 'flying' the aircraft. The Asiana pilots should have been keeping airspeed & thrust indications in their scan, regardless of whether or not they thought the A/T was engaged & would control speed. If they had done that, the accident probably wouldn't have occurred. The Turkish B737 & the Colgan Dash-8 accidents also come to mind.


Attitude, altitude, airspeed & thrust need to be monitored at all times, regardless of whether or not the automatics are engaged. This is basic aviation as far as I'm concerned.
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Old 9th Aug 2016, 01:55
  #645 (permalink)  
 
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Doh! Pipeliner, got me there! Exageration for effect��
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Old 9th Aug 2016, 02:08
  #646 (permalink)  
 
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Originally Posted by HPSOV L View Post
It has become common practice to brief the FCTM procedure for bounced landing in the last few years. I have never heard any body say "oh, and by the way: Autothrottle TOGA mode won't work".
I've certainly been warned. Another place you need to push the throttles up manually is with windshear on takeoff after V1.
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Old 9th Aug 2016, 02:29
  #647 (permalink)  
 
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Originally Posted by bsieker View Post
The scenario he describes in particular does not apply to Airbus FBW airliners. In those, a go-around is not initiated by "clicking" a button but by pushing the thrust levers to the forward stop. This will always give full go-around thrust and enable the appropriate autopilot/flight director modes. The computers will never "ignore" the pilots commanding GA thrust, regardless of whether the airplane is in the air or on the ground.
So you believe the "Pilots just flew into the trees because they didn't notice them" explanation for AF298 then?
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Old 9th Aug 2016, 02:38
  #648 (permalink)  
 
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Originally Posted by Oakape View Post
Mr Bailey is wrong, despite all his experience.
Hehehe, don't shoot the messenger, personally know Capt Bailey from B727 days in Emirates and in a way he is right but again whatever was and will be said either in the press or social networks, general public not always understand and don't need to understand therefore let this be part of future training sessions after investigators give more details.

Many on this forum speculate too much, I believe the cockpit crew was trained within same standards as was cabin crew in their part of saving lives.

And for those who continue to debate issue of TOGA been applied or not, I have googled report of French BEA, B777 Air France (maybe it was mentioned here before)...saying clearly:
====================
quote:
On approach, descending on the flight path, pushing the TOGA switches leads to selection of go-around thrust guaranteeing a vertical speed of at least 2,000 ft/ min, automatic disengagement of all of the previously selected AFDS modes, and automatic engagement of the go-around roll and pitch modes. Pressing a second time leads to selection of maximum thrust.
and conclusion:
This serious incident was due to the inadequate monitoring of flight parameters by the flight crew (and this is the part where I believe the 521 crew failed).


The following factors contributed to this:
  • Partial execution of the go-around procedure;
  • Inadequate management of the automatic systems during execution;
  • The conflict of plans of action between respecting the operators instruction and continuing the landing, which seemed to be safely possible according to the manufacturer.
=========================
unquote
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Old 9th Aug 2016, 02:56
  #649 (permalink)  
 
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Originally Posted by A Squared View Post
So you believe the "Pilots just flew into the trees because they didn't notice them" explanation for AF298 then?
Heheh that was long time ago, when there was no internet and mobile phones either...I have witnessed during my training in Toulouse the transition from the old to the new concept of flying, when experienced Capt, flying B737-400's threw his hat after few days in a A320 sim, saying:
I will retire in 2 yrs time and I don't need this...
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Old 9th Aug 2016, 03:19
  #650 (permalink)  
 
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Originally Posted by 601 View Post
If you are in cruise you probably have time to sort it out. In a go-around from a bounce, time is not on your side.
Agree 100%, another example proves B777 is capable flying safely, despite 2 tail strikes and 3 bounces....
China Cargo Airlines, CPH 2011
ASN Aircraft accident Boeing 777-F6N B-2078 København-Kastrup Airport (CPH)
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Old 9th Aug 2016, 03:24
  #651 (permalink)  
 
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I have never heard any body say "oh, and by the way: Autothrottle TOGA mode won't work". That would be because nobody has thought of it before.
Nope, not true. This 'problem' was recognised many years ago. We have a 'Rejected Landing' procedure in our 777 FCOM that covers this scenario. It clearly states "TO/GA switches are inhibited" and "Autothrottle is not available". We regularly train for it in the simulator. If Emirates does not have the same procedure and/or doesn't train for it, then questions should be asked.
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Old 9th Aug 2016, 03:48
  #652 (permalink)  
 
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the Bailey opinion piece is rubbish.i flew the 320 and the 747-400. nobody ever taught me to trust and/or depend on anything---ever.

unless times have changed, which i doubt--- its been awhile.
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Old 9th Aug 2016, 04:15
  #653 (permalink)  
 
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Costal pilot,
Not sure I agree with you there,

So much emphasis is placed on teaching and understanding auto flight and protections today, when will they work, when won't they. IMHO, they are there to save my a$$ when I'm having a very bad day. I don't fly the airplane depending on them.
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Old 9th Aug 2016, 04:15
  #654 (permalink)  
 
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But in the Dubai case, because the wheels had touched the runway, the landing gear sensors told the autoflight system computers that the aircraft was landed. So when the pilot clicked TOGA, the computers — without him initially realising it — inhibited TOGA as part of their design protocols and refused to spool up the engines as the pilot commanded.
If the TOGA switch/es were pushed during the (suspected) bounce (i.e. in the air), would the A/T and A/P produce the desired result?
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Old 9th Aug 2016, 04:23
  #655 (permalink)  
 
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Buzzbox:

'rejected landing' and 'bounced landing recovery' are not necessarily the same thing in this context. Boeing manuals don't have a direct reference, unless your airline has customised them. I don't work for EK by the way.


Boeing FCTM:

"When a high, hard bounce occurs, initiate a go-around. Apply go-around thrust and use normal go-around procedures. Do not retract the landing gear until a positive rate of climb is established because a second touchdown may occur during the go-around"

Boeing FCOM:

"The TO/GA switches are inhibited when on the ground and enabled again when in the air for a go–around or touch and go."


Actually, something doesn't add up with this theory: during a bounce you'd only be on the ground for an instant so presumably TOGA would've been selected airborne and should work.
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Old 9th Aug 2016, 05:39
  #656 (permalink)  
 
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HPSOV L:

The Rejected Landing procedure in our 777 FCOM states the following:

If a go-around is initiated before touchdown and a touchdown occurs continue with normal go-around procedure.

If a go-around is initiated after touchdown:

Manually advance the thrust levers to go-around thrust,

TO/GA switches are inhibited,

Autothrottle is not available,

Autobrakes disarm,

Speedbrake lever stows,

CONFIG FLAPS warning will occur.

Maintain flap configuration,

At VREF rotate normally,

Once safely airborne press TO/GA switches,

Perform normal go-around.
The problem with a bounced landing recovery is that the TOGA switches do not become active again until a short time (2 seconds??) after the aircraft becomes airborne. Pressing them will do nothing until after the inhibit ends. The Rejected Landing procedure in our FCOM covers both cases.

I understand the Rejected Landing procedure is not included in the 777 AFM, but I also understand that some airlines, including my employer, have chosen to include it in their FCOM, presumably with Boeing's blessing. Why hasn't Boeing seen fit to include it in the AFM for use by all operators?
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Old 9th Aug 2016, 06:17
  #657 (permalink)  
 
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Thanks Buzzbox,
Good info, yes you have to wonder why we don't all get the same stuff.
I suppose the information is all there in the basic manuals but you have to work to extract it and tie it all together.
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Old 9th Aug 2016, 06:18
  #658 (permalink)  
 
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Regarding the above procedure and TOGA being inhibited:
I have watched a pilot off a 777 flying a simulator landing in a 737, he did a nice job of the entire session ( obviously a competent pilot in my opinion) and when he reached the flare he flared nicely but didn't reduce the thrust, even when we scooted along at 20ft for quite some time. Eventually I told him to close the thrust levers. This guy was a good pilot, but when his capacity was being used he had no motor skill memory for the thrust levers. It had been eroded from years of automation in the flare which was designed and introduced to increase flight safety .
I'm not suggesting this played a role in this accident as I know nothing about it but it is relevant to the discussion of automation in this case.
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Old 9th Aug 2016, 06:30
  #659 (permalink)  
 
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This is a bit scary. There are some very good posts here by pilots of B777. What is scary for a non-pilot is, there appears to be a variation in their understanding of the system. There is also apparently a variation in standards of training and write ups in FCTM between airlines.
Another difference that is very evident. We have Byron Bailey type of pilots (A few pilots left), who rose from earlier moderately automatic aircraft, and those who have flown only the modern jets. I have seen in ME airlines cadet pilots who start on the modern jet like 777 and are now sitting on left seat. I think it will be this lot who are most vulnerable when automatic system misbehaves (or used wrongly), and you have seconds to understand and react. And when you have some one to retract the gear after a bounce, .... I need not say more. As one experience pilot once told me, "we are paid these days for the first 5 min and the last 10 min of a flight". That was on a A310 when FMS was introduced. We have gone several steps ahead with automation after that. The challenge is how to train and remember all the logic behind automation at critical times. It is a bigger challenge when one switches from Airbus to Boeing or vice versa as Asiana pilot in SFO incident testified. The discussion on this thread has become very interesting and revealing at the same time.
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Old 9th Aug 2016, 06:36
  #660 (permalink)  
 
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I've heard and read enough to form an opinion as to the most likely cause of the accident. I'm going to keep that opinion to myself to respect the wishes of the company but more importantly, to respect the pilots involved. I wasn't there, I don't know for sure.

The bounced landing is not untrained as some have said, but some airlines do not give it much time and more importantly, do not really have a formally laid out SOP for it. Automation reliance is a problem, the 320 through the trees was due to someone thinking he understood the system well, but tragically failing to appreciate a small but vital piece of knowledge. The 777 into SFO certainly had contributing factors relating to auto flight that influenced the outcome. How an individual or individuals react or recover from the startle effect is variable depending on how the atoms are put together when they were created, unfortunately some will recover from startle quicker than others. The ones you don't hear about are a combination of sheer luck and the attributes / abilities of the crew on the day. ( there for the grace of your god etc )

In another life more Orange than this one, this very subject became the main focus of a recurrent sim after various incidents around the world involving bounced landings in airbus types.. It was discovered that the programming of the spoiler extension, could under certain circumstances, result in an aircraft being high ( off a decent bounce ) with the thrust off and the spoilers at full extension. When replicated in the Sim this resulted in the aircraft dropping like a tool box onto the runway....it was an eye opener. The solution was for airbus to reprogram the spoilers to only go to half extension unless more parameters were satisfied. This stopped the aircraft plummeting quite so hard back onto the runway. When combined with a program to teach pilots how to fly away from a big bounce or land off what we described as a "skip", the hard landing rate reduced significantly.

Lessons will be learnt and Boeing may even reprogram the automation in recognition of the potential threat in situations like this. The fact remains, as people have said in previous posts, we have to keep flying the aircraft when things don't go to plan. I think it was Bob Hoover who said "keep flying through the crash".. sound advice, but how many of us really know how we would react under the same circumstances. At the end of the day we are a community and should stick together, our jobs are stressful enough with the myriad of tests, medicals and hoops that we constantly have to jump through. If we drop the ball, shouldn't we be able to rely on the one group of people who know what its like to do what we do?

BS
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