I sat next to a chatty international pilot the other week from DEN-SFO and he said that status information used to be the responsibility of the pilots, but they have simplified the system and it is now done automatically by computer according to pushback time plus standard allowances for take-off and landing. hence, any delays on taxiing mess it up.

the fact that flightaware shows surprisingly precise real-time information means that the info is being fed by satellite to the ground, but it is also clear from the flightaware - UA discrepancies that that satellite information never reaches the UA flight status system.

Last summer my parents were flying from ORD-PDX and it showed deaprted at about 8.30pm and estimated arrival around 11pm - yet flightaware showed not even departed. A little while later UA showed the flight arriving at 1.30am and then a little later again it changed to 00.15am and then to 1.00am and then back to 11.30pm (all in the space of about 45 minutes). I called UA, spoke with an agent who could only tell me what the official UA status system said, which was 11.30 at that moment.

It turned out that they were on the taxi-way, on the ground awaiting departure for 2-3 hours and they eventually arrived in PDX about 1.45am.

david