luganao
In my experience STD means when the doors are closed.
I suspect DaveReid is correct - certainly on ACARS equipped types the ATD ("out" event/timing which gets sent to company) is the time of first brake release after all the doors are closed....(in our system doors closed time is also is logged and transmitted but it's seemingly for info only/used as an aid to chase up the reason for post doors closed delays, ATD is most definitely brakes off)
For that reason I suspect
the likes of BA try to get the doors closed at the latest 3 minutes before STD so that the flight crew have got a fighting chance of coordinating pushback with ground and ATC and getting brakes are off in time to trigger an "on time" departure....
.....Back to the thread : No idea why/if the BA25 now seemingly runs late..I'm sure it was always on-time when I was involved in operating it ..
