No t if you believe recent posts
 

Rumours suggest GA called during flare, at 30-40 feet. Too high to disable TOGA. But that is just one of many "inside stories" here. Another says they bounced. That might do it.

So which inside story to believe?

What I dont believe is that a light T7 couldn't power through the problem if the throttles were firewalled. Which makes me thing there is more to this story....

One engine might struggle with the temp and pressure at dxb. Two has no trouble taking off at MTOW. I just don't get the struggle to get +ROC. Even if wheels up was a bit premature.

One more thing. A firefighter died, which is sad. But how was he that close? In this day and age you squirt foam from a safe distance inside a cabin. His death is as confusing as the crash. No disrespect intended, clearly he was putting his life on the line to save others. Credit where it is due.

Who knows?
 

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....

Still no information as to

1. "Why the GA was initiated in the first place".

2. And "Why Positive Rate was called out".

Something that's been bothering me as I've watched this thread develop, ever since I first learned (or relearned, I think I knew it once) that TOGA is inhibited by the squat switches..

If TOGA is commanded in this situation, is there any aural or visual warning?

One of the basic precepts of user interface design is that if an action is commanded and it can't happen, the user should be made aware.

I know that the cockpit is a busy place during a go-around, and that pilots are fully committed in managing the situation, but it's not such an abnormal occurance that an additional klaxon or bell would be sensory overload, and surely you'd rather know in time to push the throttles forward? Accidental commanding of TOGA in a non-safety critical situation - in the cruise or taxying to the gate - seems vanishingly unlikely to occur and if it does and there's an alert, no harm done. Presumably that's why there's a suppression circuit in there anyway.

(It's also not a complex addition: I know this is the thing that every armchair expert says, but in this case if there's anything less complicated than checking if the TOGA system is suppressed when the button's pushed, I'm hard pushed to guess what it might be)

Well, we haven’t had a statement from the authorities but we can have a good guess:

1. Aircraft not in the right place and/or at the correct speed to execute a normal landing?

2. Because the aircraft was climbing away from the ground, albeit not for very long?

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".

It's like the "she's a little bit pregnant" statement !
She is. Or she aint.
And I suspect, in this instance..... she ain't !

It may or may not be relevant to this accident but the discussion around the positive rate call may give some people pause for thought. I’ve never understood the need to try and get the gear up right at the moment the wheels are leaving the tarmac - it can only end in tears...

It is relevant for single engine performance. Which, albeit from a surprising angle, brings us to back to the point that all-engines operative go-arounds are different kettle of fish than the OEI SIM drill.

[drift=off]

OAKAPE AT 783 said Therein seems to be a problem. Positive RATE and Positive CLIMB are NOT the same except for a very brief instant when starting the process ( pull back yoke or stick ).

Consider this hypothectical say at 10k feet/

A- Thrust is constant
B- Pilot rapidly pulls back yoke and holds it for several seconds
C- reaction of plane goes
1) start to climb- positive change in altitude = positive climb
2) Rate of climb starts as positive since prior rate of climb was zero at cruise level flight
3) in a short period ( seconds ? ) climb is still positive- plane goes UP
4) BUT absent anything else changing- ( holding yoke back ) the RATE of climb will decrease, and since NO energy( thrust) has been added, eventuually, the plane will lose speed and start stall.

Now at 10 K feet - it may take several seconds to reach stall, since speeds are higher, and more energy needs to be lost re climb to reach stall conditions- and there is usually time and altitude to recover.

BUT at low altitude ( re landing ) the times and allowable altitude loss after climb RATE GOES TO ZERO OR NEGATIVE IS VERY SHORT. EG the plane can still be climbing but at a slower and slower RATE

Thus the difference between positive Climb and Positive RATE ( change per unit time )becomes more than a matter of description

Just a couple of points.....

Call "check power" and VERIFY Go Around thrust is set.

At a POSITIVE RATE OF CLIMB call "positive rate of climb, gear up........."

Hence.....


Go-Around after Touchdown

If a go-around is initiated before touchdown and touchdown occurs, continue with normal go-around procedures. The F/D
go-around mode will continue to provide go-around guidance commands throughout the maneuver.

Thus.....

You have thrust, as you have verified it
You have Positive Rate, as you have verified it.
And off you go.

No-one is venturing a solid and valid answer as to what happens to the ATs if TOGA is selected after a Touchdown or bounce.
Anyone have some material form the AOM we can share?

I remember a few years ago in an A320 sim, I was debriefed on putting the landing gear up on a single engine go around. I was PNF (FO)

GA Executed, Toga applied, however being slow to attain the proper pitch attitude we did not have a positive rate of climb. I was scanning the VSI and one point we actually were hovering around zero/descending a bit. Nothing against the handling pilot though we're all a bit rusty when we jump back in first day after 6 months :)

Once the proper attitude was attained, we started to climb and I called positive climb, and we retracted the gear etc.

I was asked "why did you delay the positive climb call" and I said because we didn't have a positive rate of climb. The checkie said yeah ok but single engine its inhibiting the performance so the gear needs to come up.

All very interesting!

I wonder if the enormous amount of speculation can be reduced to this. A reliable source stated he has direct visual evidence from a pilot who witnessed the whole event. That was the 777 landed very hard and bounced. The crew went around from the bounce, retracted the landing gear but instead of climbing away the aircraft maintained semi-level flight at about 100 feet then simply sank into the deck. This suggests that there was a failure to apply sufficient thrust to climb normally after the go-around. Exactly why the captain failed to ensure sufficient thrust was applied for the go-around is unknown as yet. But chances are there was a f**k up in the cockpit along the way.

I was asked "why did you delay the positive climb call" and I said because we didn't have a positive rate of climb. The checkie said yeah ok but single engine its inhibiting the performance so the gear needs to come up.

I'm with you Major L, in the first instance. If the a/c is within weight and the flaps have been reduced and full power is being applied, then no ROC comes from another problem. Analyse that first before jumping to conclusions. I would have thought that the gear down would not be the primary reason. If you have the power & the attitude you should have the performance. What's the rush? Has PF been a little tardy with establishing the attitude? IMHO better to wait a few seconds and be climbing away than hear the sad sound of scraping metal and think, "oops".

TOGA is inhibited for about 2-3 seconds after a bounced landing as explained in this post: http://www.pprune.org/tech-log/58256...ml#post9467694

GA after flare
 

Some discussion here about why the aircraft touched down after GA action. FCTM mentions if GA is initiated at 50 ft, acft will sink 30 ft before climbing. In this instance the pilot himself has stated the GA was selected at flare. So I think touch down is possible / normal. There is also the general doubt if GA was properly selected and monitored.

agree 100%, also
In the Boeing 777 FCTM chapter 5.66 Approach and Missed Approach it is stated:
If a go-around is initiated before touchdown and touchdown occurs, continue with normal go-around procedures.

Also take this into consideration from another B777 accident case in Paris,
The PF stated that he pushed the AT disconnect switch, located on the throttle levers, unintentionally and by mistake, instead of pushing the TOGA engagement switches(7). He then moved the throttle levers towards maximum thrust.

Imaging if UAE had a Deborah Hersman ... :)
... There would have been a heck of a lot less speculation at this point

If perception is reality, so are speculations when there are no rebuttals

at least something positive
Emirates offers EK521 passengers $7,000 in financial assistance | GulfNews.com

One passenger won't be needing that. He just won U$1m in a lottery (ticket bought at the airport) :eek:

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.

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......

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.

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.

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?

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…

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.

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

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.

.... with the gear commanded up ???

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.

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 !

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

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.

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...

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.

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

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.

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