Alexander,
 
ak> I think, the process of gliding down (without fuel) was not too long.
ak> The hydraulic system of the plane must keep the oil pressure for quite a
ak> time -- it is hermetic after all. The auto-pilot itself could work for
ak> some time from the plane reserve batteries. So, all the flaps, rudders
ak> and aileron could be controlled by auto-pilot. Or, at least, they did
ak> not dangle.
 
What you think or come-up with in your dreams is of no consequence.
 
When engines flame-out and all electrical power from the generators is lost
then the auto-pilot disconnects, this is just how those systems are
designed. What you think is irrelevant, reality is different.
 
At the same time all hydraulics are gone. In your dreams you have other
thoughts but, I'm sorry, that's how it is in reality and how it has been
designed. The RAM-turbine will provide some power for some basic
hydraulics, but when on final for landing with reduced speed, that turbine
will also run slower thereby proving less power and hydraulics is lost
again. It happened to both Air Canada and Air Transat.
 
The autopilot is not something magical that will recover an airplane when
all is lost. No, it will fly an airplane when everything is functioning and
there are no abnormalities.
 
If a stick-shaker occurs, it disconnets.
If a pitot-tube freezes-over, it disconnects.
If the fuse of the toilet-pumps blows, it disconnects.
...
 
Without engines, there is no auto-pilot and there are no hydraulics. It
cannot fly itself under those conditions.
 
 \%/{at}rd

--- D'Bridge 3.99