BOAC. I agree that the door was opened less than two minutes before the first engine shut down but why for the two hours before this why couldn't they open the door? If they knew the code they would have opened the door. If the engine quit less than two minutes after they finally got in, maybe the fuel sloshing around in the bottom of the tank caused a partial engine spool down that put the generator off line and released the door lock. I haven't flown the 737 since the new doors but our 757's require electrical power to keep the door locked. That is why we need the key lock to secure it at night with no power. I have been retired for three years so don't know what bus the door lock is on but six months ago we had a discussion here that one of our guys suggested this is what happened. It, in my mind solved the puzzle about why nobody could get in to the cockpit.
We tested the lock first flight of the day and our guarded switch in the cockpit electrically locked the door. No electricity, no lock. It would be quite a coincidence if they remembered the code less than two minutes before the first engine shut down after two hours of trying to figure it out.
I think the engine was surging in tha last two minutes and the generator went off line.
Then again, I could be wrong. Anybody else know why they couldn't get in the cockpit before they ran out of fuel?