FlightAlert departure time changing after departure.


#1

I got two alerts about a flight. The first was the ‘departure’. Then, about a 70 minutes later I got a ‘change’. The change description was regarding the arrival. However, the departure time also changed.

How does the departure change happen after the departure? Does this happen often? Here’s the data…



  "long_desc": "American Airlines #431 (B763) departed Miami Intl (KMIA) at 08:35AM EDT enroute to KSFO (San Francisco Intl) for an estimated arrival at 11:06AM PDT

Destination (San Francisco Intl / SFO): Gate 57",
  "short_desc": "AAL431 (B763) departed KMIA @ 08:35AM EDT for KSFO ETA 11:06AM PDT",
  "summary": "AAL431 has departed KMIA for KSFO",
  "eventcode": "departure",
  "alert_id": 4821355,
  "flight": {
    "ident": "AAL431",
    "aircrafttype": "B763",
    "origin": "KMIA",
    "destination": "KSFO",
    "filed_ete": "05:31:00",
    "route": "WINCO1 WINCO J73 LBV SRQ Q100 REDFN BTR HERRI MANKI MARPE CRTTR KA33S RENTT FANLO DYSSS BTY J92 OAL MOD4",
    "faFlightID": "AAL431-1373952334-airline-0602",
    "reg": "N371AA",
    "filed_altitude": 340,
    "filed_airspeed_kts": 459,
    "filed_time": 1374150908,
    "filed_departuretime": 1374150600,
    "estimatedarrivaltime": 1374170768,
    "actualarrivaltime": 0,
    "actualdeparturetime": 1374150908,
    "estimated_blockin_time": 1374171300,
    "filed_blockin_time": 1374171900,
    "actual_blockin_time": 0,
    "estimated_blockout_time": 0,
    "filed_blockout_time": 1374150600,
    "actual_blockout_time": 1374150840,
    "filed_arrivaltime": 1374170460
  },




{
  "long_desc": "American Airlines #431 flight information has changed
  Arrival Time is now Thu 18-Jul-2013 11:54AM PDT

Flight Status: En Route

Departure:
  Miami Intl (KMIA)
  Thu 18-Jul-2013 09:45AM EDT
  Gate D16

Arrival:
  San Francisco Intl (KSFO)
  Thu 18-Jul-2013 11:54AM PDT
  Gate 57

",
  "short_desc": "American Airlines #431 flight information has changed
  Arrival Time is now Thu 18-Jul-2013 11:54AM PDT

",
  "summary": "AAL431 flight information has changed",
  "eventcode": "change",
  "alert_id": 4821355,
  "flight": {
    "ident": "AAL431",
    "aircrafttype": "B763",
    "origin": "KMIA",
    "destination": "KSFO",
    "filed_ete": "05:31:00",
    "route": "WINCO1 WINCO J73 LBV SRQ Q100 REDFN BTR HERRI MANKI MARPE CRTTR KA33S RENTT FANLO DYSSS BTY J92 OAL MOD4",
    "faFlightID": "AAL431-1373952334-airline-0602",
    "reg": "N371AA",
    "filed_altitude": 340,
    "filed_airspeed_kts": 459,
    "filed_time": 1374150908,
    "filed_departuretime": 1374150600,
    "estimatedarrivaltime": 1374173640,
    "actualarrivaltime": 0,
    "actualdeparturetime": 1374155100,
    "estimated_blockin_time": 1374174240,
    "filed_blockin_time": 1374171900,
    "actual_blockin_time": 0,
    "estimated_blockout_time": 0,
    "filed_blockout_time": 1374150600,
    "actual_blockout_time": 1374150840,
    "filed_arrivaltime": 1374170460
  },



#2

Sometimes we receive updated information from another data feed that we feel is more precise than another feed, so the times might get amended after the event had occurred. It’s not a very common occurrence for past events, but it can happen.

In this case, I believe the original departure time was a “synthetic departure” that FlightAware estimated because the plane was detected as being in the air already without an data source telling us when it had departed (so we didn’t know an official departure time). Then we later received an official announcement of its actual departure time, so we updated our records to reflect the more precise departure time.