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

aussiepax 12th Aug 2016 08:07


Originally Posted by Julio747 (Post 9470810)
Early rumours talked about a bounce. Later rumours talk about a ga at 30-40ft during flare. Neither may be true. It's a rumour network....

Yes, I love the rumours too, however these two markedly different versions came from (A) the crew of an aircraft watching on from the holding taxiway and (B) the supposed brief report of the actual accident crew ! Hardly amateur observers . I found it an odd discrepancy. Ah well.

ekwhistleblower 12th Aug 2016 08:24

Maybe it's time to remove those force feedback thrust levers and those dodgy little TOGA buttons.

All the 777 guys tell me a key safety feature of the 777 is that you get 'tactile' feedback of the thrust position. It seems in 3 recent crashes: Asiana, the 737 at AMS and this one, despite having those moving levers the crew managed to get the wrong thrust on the aircraft. Shadowing moving thrust levers is pointless unless you actually regularly use them manually.

If not using the manual thrust why not use the thrust levers to engage the auto-thrust mode you want......

Volume 12th Aug 2016 09:01

With respect to the zoom-climb, inertia, momentum... positive climb discussion:

Isn´t it time to install 1940s Glider technology to our modern transport aircraft?
A total energy compensated VSI would indicate the real gain in energy, so you will not be tricked by the transfer of kinetic energy into vetical speed. Only if your altimeter and your total energy compensated VSI both show a positive indication, then you have a positive climb rate. During a bounce it should practically indicate zero. You will immediately notice, that you do not have the desired engine power.
All the instruments are today anyway controlled by computers which do have all the air- and inertia data, it would be a piece of cake to add this feature.
It may however take years for pilots to adopt to it, just like for civil pilots and AoA indicators... Never change a running system, no matter how easily it could be done.

glofish 12th Aug 2016 09:10

ekwb

I disagree. One of the more discomforting things i felt changing onto the Airbus, was the non moving thrust levers. It was either "him" in control of thrust, or me, but in any case only one. On the MD11 we were never told not to disconnect the AT (moving levers) but to anticipate any move, to assist it. It turned out, that most pilots left the AT in and appreciated the nice symbiosis: If he was slow, i gave thrust, if i was lazy/fatigued or whatever, he backed me up.

With the many Airbus 320 getting into almost half of the airlines, the Airbus manners were installed into many young pilots. Today i can almost instantly tell, if a young colleague started airline ops in a 737 or in a 320. The latter using levers more as hand-rests than anything else because almost all airlines have a "don't disconnect the AT" policy.

It would be very interesting to check how many of the pilots who were involved in such incidents lately were exposed to Airbus previously.

Don't get me wrong, the Airbus is fine, just as is the Boeing. But i slowly come to the conclusion, that those who have started jet airline flying on a Bus should remain on a Bus and vice versa with Boeing. The very short and sometimes repetitive transitions seem to prove that it adds a slice to the Swiss cheese.


@ Volume:

Another gadget will not do the trick, we have too many installed anyway. In a moment where pilots are slightly stunned, the known procedures are mishandled if there are too many.
I suggest to simply go back to basics and fly the aircraft first, with your lower back and some trained hands.

RAT 5 12th Aug 2016 09:35

Early rumours talked about a bounce. Later rumours talk about a ga at 30-40ft during flare. Neither may be true. It's a rumour network....

Apologies if already rumoured about: Not wishing to overly extend the speculation, when we should know the truth soon enough, but.......I wonder at the chicken & egg idea: was the bounce created by gear impact during a low GA? That might be difficult to decide for a spectator. It would also create quite a surprise factor in the flight deck, especially if hard. I wonder if there was a reversal of the GA decision and the thrust removed trying to land after all?

Rumet 12th Aug 2016 09:53

Given that the precise impact of TOGA switches just pre- or post-ground contact may change one or more times in short time intervals, possibly generating confusion or misunderstandings, and since even a one-off ‘Check Thrust Set’ under AT does not guarantee thrust will not be gone a moment later, how about the following SOPs:

- No manual flying with AT On, i.e. AP Off means AT also Off

- All flying ‘close to the ground’, i.e. eg all flying below 500 ft agl is to be manual (in the above sense, AP and AT both Off) in all flight phases including GA. Only exception allowed for Cat III landing, but even then in case of GA disconnect both AP and AT

- Gear up only above 500 ft agl

I realise late gear up may hinder initial climb performance, but on the other hand calling gear up on the only evidence of positive climb or ROC when close to the ground leaves one exposed if ROC becomes negative right after…

Capn Bloggs 12th Aug 2016 10:02


- No manual flying with AT On, i.e. AP Off means AT also Off

- All flying ‘close to the ground’, i.e. eg all flying below 500 ft agl is to be manual (in the above sense, AP and AT both Off) in all flight phases including GA. Only exception allowed for Cat III landing, but even then in case of GA disconnect both AP and AT

- Gear up only above 500 ft agl
Rubbish. Let's wait for the report before we start turning the world upside down. Besides, there are some types with eminently more simple throttle systems that this "one in all in" 737/777 stuff just does not apply to.

sonicbum 12th Aug 2016 10:07


- No manual flying with AT On, i.e. AP Off means AT also Off

- All flying ‘close to the ground’, i.e. eg all flying below 500 ft agl is to be manual (in the above sense, AP and AT both Off) in all flight phases including GA. Only exception allowed for Cat III landing, but even then in case of GA disconnect both AP and AT

- Gear up only above 500 ft agl

Rumet with all due respect I believe these "proposals" would just be extra threats for a huge amount of reasons.

Ian W 12th Aug 2016 12:08


Originally Posted by ArchieBabe (Post 9470931)
2. Because the aircraft was climbing away from the ground, albeit not for very long?

That there....is what's bothering me !
The thing is/has always been "Sustained Positive Rate"....
.....and that is something other than "albeit not for very long".

The problem with the landing was that the sea breeze front was producing a tail wind at low level on the final approach and over the touchdown zone. Previous aircraft had apparently gone around further out.
The runways are 4000M so we have 4 kilometers of runway it is entirely possible that toward the 2 km mark that the surface wind was once again a headwind. So the aircraft pulls up in a tail wind as it crosses the sea breeze line and suddenly has 20Kts + of extra airspeed. That could give the illusion of power coming on and initial climb (back to somatogravitational illusions again) 200ft higher and not only does the wind drop again but the inertial climb is now petering out, the gear is traveling up and the engines are not spooling up. There is no way out but down after that.

As an edit:
Can anyone provide logical reasoning for why TOGA button is inhibited with weight on wheels? The throttles are not inhibited.

HamishMcBush 12th Aug 2016 12:18


Early rumours talked about a bounce. Later rumours talk about a ga at 30-40ft during flare. Neither may be true. It's a rumour network....

I wonder if there was a reversal of the GA decision and the thrust removed trying to land after all?
.... with the gear commanded up ???

BuzzBox 12th Aug 2016 12:25


Can anyone provide logical reasoning for why TOGA button is inhibited with weight on wheels? The throttles are not inhibited.
It's designed that way to prevent the inadvertent activation of TOGA after landing, which could cause an overrun.

Ian W 12th Aug 2016 12:46


Originally Posted by BuzzBox (Post 9471560)
It's designed that way to prevent the inadvertent activation of TOGA after landing, which could cause an overrun.

In that case it would make sense to only inhibit with weight on nose wheel. As we have seen here weight on main gear does not mean committed to landing. Weight on nose wheel indicates more commitment.

ArchieBabe 12th Aug 2016 13:11

Ian W

With all respect due to you (and you may well have even described the accident itself), I do struggle so, when I hear/read people saying "...the aircraft did this" or "the aircraft did that" and "...suddenly".

To be "harsh", if what you describe is what happened, I can only point out that the crew were not new to DXB or to the T7.
It was their "time to shine". And it may well be, they didn't.

Nor was the crew "new" to flying. Whilst "the book" states, call check power and verify Go Around thrust is set....and at a positive rate of climb, call positive rate, it "allows" for, shall we call it "discretion" (It is "a book" afterall. Mere pieces of paper. It doesn't actually "fly the plane").
By that I mean, if you don't think/feel/know....then don't call "positive rate". It's at your "discretion". You judge it !
If you think "ah.... it maybe xyz", then don't call it.

I apologise if it sounds "harsh", it is not meant in that way, nor is it direct at you. It's just, I hear "...then suddenly" alot these days !

portmanteau 12th Aug 2016 13:14

Ian, Twr cleared 521 to land wind 100 11 kts ( and 20 seconds later said climb 4000 ft).

A Squared 12th Aug 2016 16:34


Originally Posted by ekwhistleblower (Post 9471354)
All the 777 guys tell me a key safety feature of the 777 is that you get 'tactile' feedback of the thrust position. It seems in 3 recent crashes: Asiana, the 737 at AMS and this one, despite having those moving levers the crew managed to get the wrong thrust on the aircraft.

The Asiana crew didn't "manage " to get the wrong thrust setting, they didn't do anything. they sat there like bumps on a log and watched the airspeed decay and the airplane fall out of the sky, until it was too late to do anything. If you;re not going to monitor your airspeed, nor monitor whether you're on the PAPI, it's really a moot point *what* your power levers do.

atpcliff 12th Aug 2016 20:22

Asiana had the Autothrottles ON. Boeing told everyone, that with autothrottles ON, you would be speed protected...the plane wouldn't overspeed, and it wouldn't stall. Turns out Boeing's information to us was incorrect.

My airline is now changing their groundschool and training because of this. Our checkairman were VERY surprised to find out that they could stall with the autothrottles ON. Hopefully this accident will prevent some more serious ones in the future...

portmanteau 12th Aug 2016 20:39

Crash landing of Sukhoi Superjet at Keflavik 21 July 2013.
Test Flight 5 on board, deliberate engine shutdown at altitude 10 feet before landing as part of test, brief touchdown, selection of toga switch on wrong engine, gear retracted, fatigue cited, all 5 survived, its all there....
see news.aviation-safety.net/category/investigation-reports/page/2/
Icelandic RNSA Final Report No. M-01313/AIG-09 31.3. 2016.

speed2height 12th Aug 2016 20:41

We will never see the QAR data... just saying.

M.Mouse 12th Aug 2016 22:51


Asiana had the Autothrottles ON. Boeing told everyone, that with autothrottles ON, you would be speed protected...the plane wouldn't overspeed, and it wouldn't stall. Turns out Boeing's information to us was incorrect.
Asiana had the Autothrottles armed but in 'HOLD' mode.

Boeing did NOT 'tell everyone, that with autothrottles ON, you would be speed protected...the plane(sic) wouldn't overspeed, and it wouldn't stall.'

The way the autothrottle system functions has always been well known. It offers protection in certain modes but not all.


It seems to me, from all the utterly pointless speculation on previous pages, that many people think a technical solution should be found to prevent what they think happened in this accident. Firstly, they have no concrete information on what happened and, secondly, it is impossible to design systems such that poor training, poor systems understanding, poor execution of a manouevre, or a combination of all those things, will prevent accidents.

I flew the B777 for 6 years. I am currently an instructor on both B777 and B787s. They are fine aeroplanes. Unfortunately, they cannot ever be designed to be foolproof in the hands of the poorly trained or marginally proficient.

In the airline world today training is cut to an absolute minimum because of cost. It is my view there are many pilots flying who can pass a skills test but when something unusual happens then a positive outcome is not assured.

I have my own ideas what happened at Dubai but I do not feel the urge to waste time and effort pontificating about the unknown.

Capn Bloggs 13th Aug 2016 01:07


Originally Posted by portmanteau
Ian, Twr cleared 521 to land wind 100 11 kts ( and 20 seconds later said climb 4000 ft).

In my view, that tape has been heavily edited. I wouldn't use it's timing as any indication of reality.


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