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-   -   Emirates B777 gear collapse @ DXB? (https://www.pprune.org/rumours-news/582445-emirates-b777-gear-collapse-dxb.html)

bsieker 8th Aug 2016 21:25


Originally Posted by DaveReidUK (Post 9467430)
In what respect, and how do you know ?

Among other things in his assertion that it would be the same in Boeing or Airbus airliners. 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.

fox niner 8th Aug 2016 21:39

New passenger's report posted on avherald:

On Aug 8th 2016 a passenger reported in the reader comments on AVH below, that the approach was normal, the landing gear was down. The aircraft touched down, however, the nose was not lowered onto the runway and the aircraft appeared to climb away again, the gear was retracted, however, the engines did not spool up. The aircraft made ground contact again, skidded along the runway with the right hand engine separating from the aircraft but still being dragged along with the aircraft until the aircraft came to a full stop.

crablab 8th Aug 2016 22:27


Originally Posted by Airclues (Post 9467499)
As most people here don't have a subscription to The Australian, I'm afraid that we are none the wiser.

Luckily it was posted here by a kind soul: http://www.pprune.org/rumours-news/5...ml#post9467384

Oakape 8th Aug 2016 22:36

Mr Bailey is wrong in his assertation that -



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

There is a newish trend to assume that the automatics are failsafe & to religiously trust them to the extent that complete control is given over to them. Some pilots follow this mantra so far as to fail to see the need to monitor when the aircraft automatics are engaged. A B777 check captain of the airline involved here stood in front of the recurrent class that I was in & asked "How many pilots does the B777 have?" The correct answer according to him was "Three - the captain, the first officer & the autopilot".


I disagree with this position. The autopilot is not a pilot. It is a pilot aid. It is not there to cover for ineptitude or lack of sufficient, suitable training, despite what management may think or desire.


Simply stated in relation to what it appears may have happened here, you do not just hit TOGA in a go-around & then totally ignore the thrust lever position (B777) or the thrust indications on the upper DU. You are required to ensure that the automatics have given you what you have requested of them & if they haven't, DO IT MANUALLY! This is what is meant by 'Fly the aircraft'.


Over reliance on the automatics is a hot topic these days & has been done to death on various threads here & on other websites. However, it is becoming more prevalent in the industry as inadequately trained or incompetent or lazy pilots (or a combination of all three) become more widespread in the industry. Sounds harsh, but that's the truth of the matter that I see almost every time I go to work. A number of recent accidents also highlight this problem.



Maybe Mr Bailey's statement that 'pilots are rigorously trained to trust supposedly failsafe automatics' is at the very heart of the problem.

601 8th Aug 2016 23:44


'pilots are rigorously trained to trust supposedly failsafe automatics'
No computer programmer can cover all the real world "if then" situations.
What is needed is a big red button labelled "Tiger Moth Mode"

Ask yourself how many times have you uttered "Why is it doing that".
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.

tdracer 9th Aug 2016 00:59


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.

HPSOV L 9th Aug 2016 01:08

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.

pipeliner 9th Aug 2016 01:39

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.

Oakape 9th Aug 2016 01:55


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.

HPSOV L 9th Aug 2016 01:55

Doh! Pipeliner, got me there! Exageration for effect��

Airbubba 9th Aug 2016 02:08


Originally Posted by HPSOV L (Post 9467604)
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.

A Squared 9th Aug 2016 02:29


Originally Posted by bsieker (Post 9467450)
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?

bobdxb 9th Aug 2016 02:38


Originally Posted by Oakape (Post 9467419)
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

bobdxb 9th Aug 2016 02:56


Originally Posted by A Squared (Post 9467641)
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...:{

bobdxb 9th Aug 2016 03:19


Originally Posted by 601 (Post 9467560)
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)

BuzzBox 9th Aug 2016 03:24


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.

costalpilot 9th Aug 2016 03:48

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.

JNPS 9th Aug 2016 04:15

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.

NSEU 9th Aug 2016 04:15


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?

HPSOV L 9th Aug 2016 04:23

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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