There was a flight I operated into BFS earlier this year. Our APU was inop and the ground staff were supposed to be plugging ground power into the aircraft so that we could then disembark the aircraft without it getting plunged into darkness (was around about 21:00 at the time). The ground staff in BFS plugged in a GPU, it didn't work, tried another, didn't work, tried a third - didn't work so we had to disembark pax via door 1R and leave the number 1 engine running. The ground staff eventually realised that the problem with all three of the GPUs was that they had failed to start them!!!
Whilst it wasn't ideal for the pax to disembark via the right hand door, and totally unacceptable to disembark with the number 1 engine running, the pax had been sitting on the aircraft for nearly 30 minutes with unacceptable heat (approaching 38c) as the aircon wasn't working due to the inop APU.
The ground staff were given a bit of a talking too by the Captain when the problem was realised!
