Re: RAT
True enough. Get a double engine failure & resulting loss of power and you end up in a reversionary mode with the RAT deployed and unnecessary systems shut down, including some cockpit displays. Between RAT, batteries & hydraulic accumulators you have enough control to keep the aircraft flying, and to try to deal with whatever happened.
There is also limited mechanical backup for some of the control surfaces. Exactly how much depends on the aircraft type. Airliners at least will glide by nature (if sufficient height exists they always tend to recover into a glide, assuming the airframe doesn't fail first) so you can cope with limited direct control and/or no engines.
As for fallback/override modes, these exist but are basically options for deselecting some of the control filtering. With everything active the FCS will stop you exceeding various comfort and performance parameters eg. AOA, roll rate etc. etc., sometimes known as 'carefree handling and manoeuvring' because as long as you don't hit anything you don't have to be too careful about what you do with the controls. Though some of the cargo might complain!
Switch out the FCS (press the button or if feeling brave pull circuit breakers) and you end up in direct law, at which point you effectively have direct unrestricted control of the aircraft. This feels quite good to fly as you can explore the handling which is much sharper when unfiltered; the downside is you could end up with serious problems as there's nothing to stop you doing something unrecoverable, or which might break the aircraft except your own actions at the controls.
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Re: lack of fire. The tanks would be pretty empty after the flight given the distance, though I guess the main reason for no fire would be that the landing gear ripped through the gear well as the mountings failed under stress, but this part of the wing didn't include any fuel storage as the gear well, gear support structure & main spar would have taken up all the useful space at that point. Hence no ruptured tanks, and no fire.
Also remember that near empty tanks are actually more dangerous than full ones as they tend to explode due to the fuel vapour. The 787 will have a standard-fit inerting system to prevent this, but the 777 doesn't yet have this option, and I don't think anyone has retrofitted so far.
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Whatever happened (seems like engine control/avionics failure?) it looks like they just didn't have the height or airspeed to do much about the situation, gear down late on an approach really isn't the best time to try to deal with this kind of thing. A couple of minutes earlier and an unpowered approach might have been exciting, but the glide & touchdown would have been much easier as there'd be time & margin to adjust, and very few would probably have known what had happened unless they read incident reports.