FL1TPA From United States of America, joined May 2004, 258 posts, RR: 0 Reply 1, posted (9 years 3 months 5 days 10 hours ago) and read 1317 times:
This sounds like more of a problem with the ground power unit (GPU) than the auxiliary power unit (APU) onboard the aircraft. If the Captain has completed his taxi to the gate and not started the APU, he's probably counting on GPU power when he parks. He then just shuts the engine(s) down when given the signal by the ground crew that GPU power is connected. The power "flickers" you see mostly occur when the pilots switch between sources GPU / APU /
Engine. The Engines each have a generator called a CSD (Constant Speed Drive). If the CSD on one engine is INOP, the APU MUST be started and operated continuously in most cases. If any 2 of the 3 generators onboard (CSD1 / CSD2 / APU) are INOP the A/C cannot be dispatched.
The flashlights bit probably occurred when the GPU cut out before the APU could be started - resulting in a dark cabin. Hope this helps.
"Looks like I picked the wrong week to stop sniffin' glue."