Posts about: "Flaps (All)" [Posts: 165 Pages: 9]

can you ask him by any chance what the outcome would be with f15 or 20 speeds, but in a F5 config and a rotation at VrF15 ?
and retract the flaps to 1 instead of gear ?
sorry I don\x92t know if that has been tested already.

The rotation in the video appears normal and tail clearance is normal as well. That suggests VR was correct as well as the flap setting.

A low level ALT Capture with autopilot ON would have made the aircraft pitch down quite hard. The same if flown manually and FDs followed (like Emirates). This aircraft did not pitch down.
If flown manually and pitch kept normal, the speed would initially drop, then increase as the speed dropped under the \xabcapture\xbb speed.
This aircraft was not flown pitch down into the ground.
Flaps instead of gear has been tested to be possible to fly out of.

Two engines stopped. At the same or nearly the same time.

The possible billion dollar question is why?

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)

In prior posts, I used approximately the same numbers and came to a similar conclusion (we can't rule out the possibility that there was a least idle thrust available after the loss of thrust), using a guess of a 44% reduction for the configuration from a max L/D of 21. Starting with the height and distance being approximate however, we also don't know what the airspeed/angle of attack was at any point in the descent versus the speed for the maximum (and unknown) L/D for the gear and flaps extended and the RAT out, the amount of headwind, the increase in L/D in ground effect (at a height less than the wingspan) over other than a smooth surface, thermal activity in a urban area, the distance gained in the flare at the end, etc.