>One other question: Why do the airlines have 0630 "departures" only to languish out
>on the taxiways for half an hour???? I understand the noise abatement procedures and
>all of that, but why publish a flight departure time that cannot realistically be met? (yes I know
>that departure time is pushback time, not liftoff time)
If you know departure time is pushback time, then you know the 0630 departures left at 0630... on time. The real question is why leave the gate prior to earliest takeoff time of 0700. Two reasons actually.
1. ATC operates "first come, first served." First to call ground control for pushback gets first available takeoff and/or eastbound departure slots. For example; I used to fly AA's 0645 departures to ORD/DFW. If we were ready and called ATC 2 minutes prior to departure time for pushback, we were usually 1st or 2nd in takeoff line. If we were not ready until scheduled departure time, we were usually 10-15 for takeoff. That means up to 45 minute wait before takeoff!
2. Terminal gate space is limited so first wave of departures leaves and second wave of departures are pulled from remote parking spots to the gates. Leaving prior to 7am permits these remotely parked aircraft to be moved to gates sooner and therefore second wave of takeoffs can occur sooner than otherwise possible.
>It's a riot to go down there in the morning, just before 0700, when the first 'wave' of
>departures have pushed. The planes are lined up and scattered all over the place. Some of
>them taxi all the way around the field, and wait on the other side (the side that the tower is on)
Actually, we're not scattered all over the place, but rather we're lined up on one of the two available taxiways to use the one available runway. Use of the west side during this time period is normal provided no small aircraft are using it. With the 19L construction going on, normal procedure is to send two aircraft to the west side with the rest lined up on 19L facing north. Aircraft that can not fit onto 19L are usually held on the gate so taxiway A is open to tow aircraft from remote parking to open gates. By 0730 or so runway 19L becomes usuable for light civilian planes and all remaining airliner departures line up on taxiway A awaiting departure.
At night, the reverse occurs as runway 19L is used for inbound taxiing aircraft trying to get to gates and taxiway A is used for towing aircraft to overnight parking spots.
*NO CARRIER* -- A Naval Aviator's worst nightmare!