Posts about: "Flap Retraction" [Posts: 66 Pages: 4]

If decrease in thrust not by transition to climb thrust due to early inadvertent flap retraction and pilot action on fuel control switches from accomplishing dual engine failure memory items, then fuel cavitation /fuel fumes lock may be a cause. Just saying.

Yes. But I have not flown this scenario in the sim. Way too many protection to take off without proper configuration which leads me to believe loss of lift due to flap retraction. 1100 hr FO ……..

I\x92ll reply to my own post in light of the RAT deployment. If true then this opens up to a lot more. And simply guessing with grainy video a fools game. All I saw was gear down to high Into the climb. This should not happen under any circumstance . Dual engine failure would explain the loss of lift obviously. Early flap retraction also. One would hope it\x92s not a simple as that: cheers

On item 1, the TCMA issue should have been fixed, it does fit the sort of issue that occurred here. TDRACER can talk to that, and has done in 2019 and again in post 792. As to flap auto retraction, the B787 like all Boeings has a gated flap lever, and the flaps are only able to move independent of the lever by flap load relief. That would not have caused a loss of thrust, and in this case it is evident that the event is a thrust loss not a CL loss.

On item 2, the video shows no asymmetry at any time, so there is only a symmetric failure of the engines possible. Back on a B747 classic, you could chop all 4 engines at the same time with one hand, on a B737, also, not so much on a B777 or B787. I would doubt that anyone used two hands to cut the fuel at screen height. Note, there was a B744 that lost one engine in cruise when a clip board fell off the coaming. Didn't happen twice, and it only happened to one engine.


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Neila83 is correct, the gear tilt pre retraction is rear wheels low, and at the commencement of the selection of the retraction cycle (generally), the first thing that happens is the inboard MLG doors start to open below the wheel well and then the bogie is driven to front wheels low. (There is also an option that the inboard gear doors start to open early as a result of WOW sensing to improve the SSL climb limit). [my bad, for the B788 Capt Bloggs informs us the gear door sequence is after the tilt, not before, the B789 has the before tilt, the option for the door open at rotate is separate]

The inboard doors do not appear to have opened in this case, yet, the gear is forward wheels down. This appears to be out of sequence. TD may have better knowledge on the options that exist with the B788, but this is not looking good at this time.

There is enough in the way of anomalies here to end up with regulatory action, and airlines themselves should/will be starting to pore over their systems and decide if they are comfortable with the airworthiness of the aircraft at this moment. A latent single point of failure is not a comfortable place to be. Inhibiting TCMA might be a good interim option, that system could have been negated by having the ATR ARM switches....(Both)... ARM deferred to the before takeoff checks. The EAFR recovery should result in action within the next 24-48 hours. Boeing needs to be getting their tiger teams warmed up, they can ill afford to have a latent system fault discovered that is not immediately responded to, and the general corporate response of "blame the pilots" is not likely to win any future orders.

I think we are about to have some really busy days for the OEM.


Not sure that Neila83 is that far off the mark at all.

Very unlikely IMO as it's difficult to imagine even a low time pilot making this error--not impossible of course.

If you are correct and early flap retraction instead of gear.....why was the rat out? It is almost assuredly deployed. Why did the video not indicate high thrust on the engines? The are silent. Pulling the flaps too early won't cause an engine failure(s) ans won't cause the rat to deploy.

Even if inexperienced FO retracts flaps early certainly a senior captain who is also per some reports a training captain.....certainly he would have gone for max thrust and lowered the nose to try and fly out of it. Certainly he would have raised the gear?!?!?!

Still not making sense....unless....and I posted this earlier.....was it intentional?!?!?

Do we know for certain there was a mayday? If yes, do we know for certain is was the captain? Could the captain have possibly become incapacitated around VR and low time FO totally unprepared and froze?

I am always amazed how foreign airlines put super low time FOs in biiiiig planes.....scary. i chatted up an early 20 somthing Ryanair FO and she was excited bc she just hit 300 hrs. I said oh 300 on type (737)?? She says no.....300 hrs...total time. And she's flying internationally!!!!!!

DISCLAIMER: Poster (a) is one of the (apparently quite numerous) lawyers following this thread; (b) a long-time forum lurker and aviation enthusiast who loves studying FCOMs for fun (to each his own, I guess); (c) has followed and read this thread from the start.

What I cannot do is add new theories or uncover any new facts the actual experts have not already thought of. However, since summarizing and structuring information is one thing lawyers tend to regularly do (and sometimes even do well), here is my attempt at a useful contribution to this thread: an attempt to summarize the main theories discussed here since day one (which I think hasn't been done for quite some time) in the hope that a birds-eye view will be helpful to those who have not read everything since the beginning or might even trigger some new flash of inspiration for someone more knowledgable than me. I have focused on the cons since there does not seem to be enough evidence to come to any positive conclusion.

I shall try to be concise and to refrain from personal evaluations of my own. Of course, no disrespect whatsoever is intended towards all those who have contributed to this thread and to the individual theories, one or combinations of which may turn out to have led to this tragic outcome. That arguments can be made against every single theory that has been propagated seems to be the result of the highly improbable and unusual nature of this deplorable event and certainly not due to any lack of knowledge or reasoning skills in this forum.

DEAR MODS: If I have distorted anything or if, meaning well, should have achieved the opposite \x96 I guess you know where the delete button is\x85

Anyway, here goes:

A. Misconfiguration or wrong takeoff data
Widely refuted, since

• rotation, takeoff and initial climb seem normal;
• likely extreme errors would have been required to have such tragic effect (the fuel tanks should have been only about half full, so not close to MTOW);
• there is strong evidence that at least some flaps were extended for takeoff (post-crash photo, perhaps also visible in video from behind)

B. Flaps retracted post-takeoff instead of gear
Still brought up from time to time. However, widely disregarded due to

• the fact that with two working engines an inadvertent flap retraction should easily be recoverable, even with gear down;
• strong indications that hydraulic and electric power were lost (audible/visible indications of RAT extension, survivor statement, lack of engine noise, position of MLG bogies).

For a while, the forward tilt of the bogies as first part of the retraction cycle was seen as additional evidence that the gear had been selected up. However, it has been pointed out that the forward tilt and the opening of the gear doors occur almost simultaneously so that it seems unlikely that hydraulic power was lost in the split second between bogie tilt and gear door actuation. It is now assumed the forward tilt of the bogies was merely a consequence of the hydraulic power loss.
It should be pointed out that the question of "RAT in or out" was for a while the most contentious in this thread.

C. Low-altitude capture
Still argued, even if refuted by many since

• inconsistent with apparent loss of hydraulic/electric power;
• PF would have been flying manually (however, A/T reaction would have been unexpected for the PF);
• should have been recoverable (unless one assumes that the crew (a) remained unaware of the changed FMA annunciations although alerted by the unexpected FD commands; and (b) was so startled that an A/T thrust reduction was not noticed and corrected, even though the PF was apparently sufficiently alert not to follow the FD commands).

D. Loss of both engines at or shortly after rotation
Various possible reasons for this have been discussed:

I. Bird strike/FOD

• Would have to have occurred simultaneously due to lack of rudder/aileron input indicating symmetric thrust.
• No remains/traces on runway, no visual indications (flocks of birds, flames, structural engine damage).

II. Fuel-related III. Improper maintenance
Unclear which maintenance measures could possibly have been performed that would have resulted in simultaneous loss of both engines. No apparent relationships between malfunctions reported by previous passengers and essential systems.

IV. Large-scale electrical fault (e.g. due to water in E&E bay)
The engines will continue to run if electrical power is lost. FADECs are powered independently.

V. Shutdown of engines by TCMA
A parallel is drawn to the ANA incident. However, this would require not only a fault in the air/ground logic but also a sensed discrepancy between T/L position (not necessarily idle) and thrust output on both engines simultaneously.

VI. (Inadvertent) shutdown by flight crew VII. Malfunction/mishandling of the fuel cutoff switches (most recent)