Originally Posted by
TURIN
It's been a long time since I worked on the 747 but I thought the high lift devices were linked mechanically so how does the loss of one or even two hydraulics systems cause asymmetrical deployment of flaps/flaps?
Your are correct TURIN, but I think some contradictions are misleading, as indeed they are mechanically connected by the drive shaft system: the inner
T/E flaps are driven by torque shafts to port and starboard sides through gear boxes etc; same with outer T/E flaps in a separate drive torque shaft layout.
Similar with L/E devices.
In my type rating cover, only the BAC1-11 had a back up drive train, a secondary drive shaft system which rotated with the main, but had a lost motion coupling, if and only if a main shaft was sheared/ disconnected, say anywhere along its length, this second drive would catch up driving from the outer wing inwards.
Lot of maintenance items, lubrication needed.