B757 utility buses

[fingal flyer]

Just wondering why they both go off when apu is running electrics and thrust levers are advanced.IE engines shutdown.Suspect it is load shedding due to a/c logic suspecting double engine failure but can anyboby help an ignorant pilot.

[Short_Circuit]

Yes f.f., it is load shedding due “single power source” supplying buses with thrust levers advanced.
S_cct

[NSEU]

It's probably like the 767 which loadsheds in the air with a single power source. On the 767, Boeing defined "in air" (wrt to loadshedding) as weight off wheels(bogey tilt) or thrust levers advanced (presumably as a backup for the gear tilt).

Rgds.
NSEU

[flyboyike]

The CRJ does the exact same thing. It doesn't even have to be in the air. All it takes it to be single-gen, main door closed, flaps out of zero.