Someone mentioned putting ground air conditioning on. It is uncomfortable in warm weather to be stuck in an aircraft with no a/c and I guess, if it had been daytime the pax would have been disembarked.
I'm wondering if the reason for no a/c was that, with engineers in the u/c bay, they didn't want to pressurise the a/c and/or bleed air ducts.
As I've said many times before: "There's always a reason." It's just that finding it is sometimes difficult
