Originally Posted by
Check Airman
If the pax are already on, I believe the only restriction is that the door must be open.
It can be a bit more than that depending on the company and government rules such as seatbelt sign off, Purser advised, min F/A for the flight onboard, PA to pax reminding about no smoking, F/A's at their assigned exit ready to arm slides if necessary, no blocking of designated fueling exits(such as by a catering truck or on the inside.), jetway(or stairs or PTV attached to aircraft with door open(or partially open if weather dictates), no oven or coffeemaker operation, an assist person for anyone who is disabled, pilot on flightdeck in communication with groundcrew, no HF operation, no connecting/disconnecting of GPU, some maintenance restrictions that could cause sparks, minimum electrical storm distance, and a few other smaller items.
A check airman loves to ask these detailed items to their trainees.