We recently started exploring flight aware api’s and we are trying to understand how to identify departure delay information of yet to depart aircratfs.
We saw an api FlightInfoEx where i was able to find the delay in departure of an aircraft after it had departed (scheduled depart time minus actual depart time).
But we were wondering how to find out departure delays of yet to depart aircrafts.
Flight status for delay, cancellation info
You would probably want “estimated departure time” to predict if an undeparted flight is delayed and when it is expected to depart. However, FlightXML2 currently does not expose that value but we are expecting to provide it in the next major release of FlightXML, currently in development.
Until then, you can approximate what “estimated departure time” would be by computing (estimatedarrivaltime - filed_ete), which are both returned by FlightInfoEx.
I just tried using this method to get a possible delay, but this method is not very reliable.
$flightInfoEx faFlightID : QFA400-1474522510-airline-0052 ident : QFA400 aircrafttype : B738 filed_ete : 00:44:00 filed_time : 1474522510 filed_departuretime : 1474660800 filed_airspeed_kts : 441 filed_airspeed_mach : filed_altitude : 370 route : DCT DOSEL Y59 TESAT actualdeparturetime : 1474661400 estimatedarrivaltime : 1474665300 actualarrivaltime : 1474665325 diverted : origin : YMML destination : YSSY originName : Melbourne Tullamarine originCity : Melbourne, Victoria destinationName : Sydney destinationCity : Sydney, NSW
Using ((estimated arrival time) - (filed estimated time enroute)) would in this case mean a delay of 31 minutes.
This however can’t be right. The flight is tomorrow morning, in around 21hrs. All the info says is filed times and a planned ETE.
This info can also mean that they take off on time (at 6AM AEST) and arrive at 6:44AM AEST. Which would mean they are 31mins ahead of schedule.
Has anybody found a better way to get delay for a given flight?
That flight has already occurred, so you should always use the actualdeparturetime/actualarrivaltime values instead of estimated ones.
The technique described is only useful for flights that have not occurred yet and you don’t have an actualdeparturetime yet.