I've just seen a YouTube video of a 777 autolanding. The PVD comes alive during rollout after A/P disengagement.
It wasn't armed after touchdown. If the system is switched off completely after T/O (memo message/s removed), how did it rearm itself with an in-air inhibit?
Also, I experienced some (reproduceable) unexplained behaviour on a 747-400 today. If I pull
all MMR CBs and arm a PVD, the PVD runs through its selftest, then the shutter remains open! Randomly, it scrolled left or right at various speeds or in some cases, stayed still. This weirdness, however, was inhibited during IRU alignment and in ATTitude mode (not sure about full NAV).
I'd love to know which committee designed this system
Cheers