Originally Posted by
AtoBsafely
I believe he was suggesting that water can freeze up the screw jacks so that the hydraulics can’t turn them.
I experienced that with the flaps stuck up on arrival after a departure in heavy rain. We were just beginning the checklist when things thawed out and in another minute were working normally.
In this case, I would expect that a frozen stab problem would have occurred earlier as the trim changed with IAS during descent.
I experienced this on the 727 many years ago, however Boeing changed the screw jack lubrication system and that seems to thave resolved any further issues.
Never had an issue on the 767 200/300 both as PFE with Ansett and AP with Qantas.
There was and AD issued regarding screw jack lubrication of recent times.