Ok, nobody mentioned this or at least I can't see this. If the brakes are very hot due to use during taxying the landing gear is often left down longer than usual to cool the brakes to a safe temperature before retraction (see Swissair 306) It was also very hot on the ground today
Comments ? I'll get my coat...
doesn't have to be hot brakes, there are a number of 787 MELs which require gear down after takeoff, the most extreme I ever applied got us to FL150 before we could retract it.
very doubtful this would be the cause of this accident however
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Come on, people. If it went into altitude hold, yes, the power probably would come off, but only to maintain the current airspeed. It would very quickly start powering back up as the aircraft attempted to sink and was countered by the PF. But the power didn't come back up, that being obvious from the increasing AOA during the descent.
In any case, there wouldn't be a sudden level-off because the PF is still l hand flying below 200ft. Do you think he'd blindly just jam the stick forward to follow the FD at such a low altitude?
As stated before, if even only one of those engines was running, there's no way it would have descended, slowing down, as it did.
Thank god someone has pointed out the absolute cobblers some people who claim to have some experience of this type (and other completely unrelated types) have been spouting. And if anyone else wants to erroneously compare the 757/767 low level EPR ALT CAP scenario , that keeps the TO thrust on, it doesn\x92t reduce it! This is truely one of the worst of these accidents threads I\x92ve read in a long time, I pity the mods.
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waffle waffle
Remember that Airbus accident where the aircraft thought it was landing, while the pilots wanted full thrust, and they crashed into a small forest because some kind of idle is all they were afforded by the system?
waffle
Thoughts, especially by someone who flies the 787?
I do remember that accident, the pilots never commanded full thrust until it was too late, they put the aircraft in a position it shouldn\x92t have been in and didn\x92t understand how it worked. I\x92m guessing you don\x92t as well, either way it\x92s totally irrelevant to this accident
I\x92ve flown the 787, my thoughts are I know this \x93I\x92m just asking questions\x94 is the current Zeitgeist but sometimes it\x92s best to remain silent if you don't have a clue what you\x92re talking about.
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I\x92ve had a look at the Honeywell spec sheet for TL type switches. They are a common type with many available configurations and are essentially a normal looking snap action switch. The locking feature is an add-on which can be specified. I have to say that from the diagrams, the locking mechanism doesn\x92t look that robust and I\x92d guess that it is subject to wear which was probably the basis of the SAIB. Given that this is a mechanical locking device seeing frequent use possibly with less than full mechanical sympathy it is possible to see how wear would occur making the lock less effective. This does beg the question of whether a check on the mechanism has made it into maintenance routines. ( Note - the locking mechanism appears to be the same for all TL switch types) . Those familiar with the switches - what do you think?
For the avoidance of doubt, the above is a technical observation on the switch type NOT a causation theory for this accident.
this isn\x92t the type of switch fitted to the 787 as a fuel control switch, totally irrelevant but has generated yet more nonsense. The switches are spring loaded (or so it feels) in addition to having a massive block to prevent inadvertent operation in either direction. Anyone suggesting they could be accidentally \x93knocked off\x94 is so clueless about their operation it\x92s actually painful to rebut
Don\xb4t get me wrong. But this is exactly the attitude - some might call it arrogance - which will lead to accidents or for bugs to sneak in sooner or later.
The attitude that posting diagrams of a switch that isn\x92t fitted in the role being attributed to it is nonsense constitutes arrogance now does it? Or is it the suggestion that unless you\x92ve got an idea how a system works in the accident aircraft type you shouldn\x92t post idle speculation? There are an amazing array of combinations of issues that could have caused this accident, speculating wildly on each and every outlandish possibility contributes nothing but noise.
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It is very, very, very close:
Both engines failed: yup, both engines have failed.
Triple hydraulic pressure low: either you've been hit by a SAM/uncontained engine failure causing massive fluid leaks, or both engine driven pumps have failed (likely because the engines have failed) and all four electric pumps have failed (because the engines have failed).
Loss of all electric power to flight instruments both sides: total AC electric loss, and I think battery/static inverter too? Given four generators and four buses, either massive electrical failure (swimming pool in E&E bay) or engines have failed. Note failure of an individual contactor that can tie two buses together should not cause a quad-bus outage.
Loss of all four electric motor pumps: total AC failure, see above.
thanks for posting the conditions, while likely it deployed as a result of a simultaneous loss of both engines, not the only circumstances then.
