Airportboards offset

I’m using flightXML3.0 API to get arrival flights on specific airport with BRONZE account, when i query data with below request, it only returns 15 records, and says next_offset 54
http://flightxml.flightaware.com/json/FlightXML3/AirportBoards?airport_code=xxx&type=arrivals&filter=airline:xxx

then I added parameters to set offset = 15, it returns 12 records, and says next_offset -1, how should i use offset to get more data
http://flightxml.flightaware.com/json/FlightXML3/AirportBoards?airport_code=xxx&type=arrivals&filter=airline:xxx&offset=15

I just noticed when I put a howMany option on my request, it do help this API behaves more consistently,
http://flightxml.flightaware.com/json/FlightXML3/AirportBoards?airport_code=xxx&type=arrivals&howMany=10&filter=airline:xxx

set howMany=30, it returns “num_flights”: 25, “next_offset”: -1,
set howMany=10, it returns “num_flights”: 10, “next_offset”: 36,
set howMany=10&offset=36, it returns “num_flights”: 8, “next_offset”: -1,

but I still can’t understand:

  1. why the returned next_offset is 36 instead of 10, is it offset index before filtering
  2. why the first query returns 25 records, but the second & third queries returns 18 records in total
  3. what should I do to fetch records over 30? I am sure there are more flights arrived at this airport even at the same day, but the next_offset value returned from first query is -1
  4. I also noticed some of the flights returned does not have tail number, which is needed in my app, is there anything we can do to fix it?

I am looking for equivalent xml2.0 API (Arrived), which I guess should be more stable. But I don’t see a way to filter result set by specific airline, for example i only want EVA flights returned
http://flightxml.flightaware.com/json/FlightXML2/Arrived?airport=TPE
Any suggestion?

I have posed some questions to our team regarding your questions. It would appear that there is counting happening prior to the filtering, causing next_offset to be different than expected. This should handle questions 1-3. I will provide more insight when I hear from the team. As for question 4, I looked through about 30 EVA flights and it appeared we had the tail for all of them.

FXML 2.0 does not have an airline filter built in, i believe. You may be able to do it in an undocumented way, but I am not aware of a way to do it.

For FXML3.0, my major concern is that i can’t get enough historical arrival flights. like below request, it only return 11 records, at first call,
http://flightxml.flightaware.com/json/FlightXML3/AirportBoards?airport_code=TPE&type=arrivals&filter=airline:EVA

The howMany, offset, and next_offset values will skip over rows that you don’t have access to (in this case you are using a filter). The num_flights returned can sometimes be less than the requested howMany even when there is another page of data (next_offset != -1). Next_offset should not be assumed to be offset+howMany when there is another page of data