Posts by user "Pinkman" [Posts: 6 Total up-votes: 8 Page: 1 of 1]¶

Originally Posted by Australopithecus

1. The original video, not the video of a video, has the distinctive audio signature of a deployed RAT.

2 That video shows something dangling down where the RAT is located.

3. There are no typical engine sounds heard.

4. The flaps are extended in that video, and the slats at least are extended in the wreckage pictures.

5. There was no tail strike, so you would conclude that the performance figures were at least close to the actual mass and thrust required.

6. Given the above, and the straight flight path without rudder deflection which ends in a crater instead of Gatwick, you pretty much have all the evidence you need to conclude that there wasn\x92t sufficient thrust and that what little thrust there may have been was symmetrical.

7. While there are many things common to both engines, the most frightening are a system failure and inappropriate crew action. Oh, and some previously unheralded MX action.

Originally Posted by CHfour

With the information we have accumulated so far, is the following a possible scenario? Normal departure up to VR, then a total electrical failure at lift off (possibly as the ground/air logic switches to air.) All hydraulics lost and cabin lights flicker plus RAT deploys. All fuel boost pumps fail so engines only have suction feed. Engines roll back. The aircraft seems to me to have gone too far to have suffered a total loss of thrust at lift off. There must have been some energy being provided by the engines? Such a system failure "can't happen", of course but nothing is impossible!

Originally Posted by Aerospace101

I too watched his explanation with interest. However I believe he is not considering the possibility of C hydraulics failure prior to wheels lift-off, because I speculated this is the more likely reason the gear trucks remained in a forward tilt position, see my earlier post here . I believe the crew never got as far as calling for the Gear Up... many possible reasons for this, flickering instrument screens during the electrical switchover to battery power, flurry of EICAS messages. For any of those things happening around time of rotation, I would be advocating delaying gear up decision until safely climbing away above AA and as a crew you have chance to discuss safest course of action. Not putting the gear up shouldn't kill you.

Point is the gear truck tilt is a clue of a C hydraulics failure, but we cant determine if hydraulics failed prior to wheels off runway or prior to gear doors opening in retraction sequence.

Originally Posted by framer

User989 thanks for a nice summary
I am at risk of turning into one of those folks who gets their mind locked on one possibility and keeps banging on about it but here goes;

If the authorities determined that the accident aircraft had been treated by maintenance for microbial growth in the fuel tanks within the last week or so, and they suspected that that procedure was carried out in a way that could result in fuel contamination, then that would explain

1/ No other aircraft being affected
2/ No measures taken at the airport
3/ No AD\x92s from the regulators
4/ No grounding of 787\x92s
5/ Flight profile
6/ Rat deployment etc etc

I agree with your statement that dual flameout due fuel contamination is very unlikely, but we ARE dealing with something that is very unlikely. I favour the theory because an error in treating the fuel is so predictably human and simple, and a dual engine failure being related to fuel is also a simple and obvious idea, and it satisfies all we know both about the aircraft\x92s behaviour, and the authorities behaviour post accident.
I posted a report earlier of a 787-8 powered by the same engine type have both engines roll back sub-idle within a minute of each other while airborne due to this, so we know it can happen in theory.

Now\x85\x85I want to be clear that I\x92m not saying I think I know what happened, I\x92m an average Joe with my hands full just flying the line, but I am a bit surprised that the idea of \x91fuel contamination specific to that airframe\x92 doesn\x92t get discussed more on this thread.
Thanks again for the clear summary of discussion thus far.

Originally Posted by The Brigadier

It seems to me that there must have been further dialogue after the bland "I didn't". To have nothing reported after that two-line exchange, until the MAYDAY at 08:09:05, is a highly suspect omission from the interim report. In a two-crew cockpit, facing a sudden dual engine rollback just after rotation, I find it very hard to believe that this two-line exchange was the only interaction captured.

Originally Posted by Nick H.

They are guarded. To refresh everyone's memory here's a photo from the previous thread.

Originally Posted by Contact Approach

Having studied HF, how many flights since the beginning of time have BOTH of those switches been inadvertently moved during takeoff? If that number is 1 or less you were probably better off studying statistics.