Interpret empty, null, and changing results

An Enhanced Radar API request can succeed and still return nothing, a null, or a result that changes later. This page explains what each of those means, so a display built on the API tells your users the right thing.

Coverage

Situation	What it means
Facility search finds an airport	Only that the facility exists. Search covers every facility we know about, including ones we do not cover. Check `GET /api/v0/facilities` for coverage.
A facility is in `GET /api/v0/facilities`	We cover at least one of its channels. Check each channel’s `is_available`.
A channel has `is_available` set to `true`	The API serves that channel’s data. It does not report whether we are receiving the channel right now, so an available channel can still return no transmissions for a period.
A channel has `is_available` set to `false`	The API returns no data for it. ATIS channels are always `false`. Email support@enhancedradar.com with the `atc_channel_id` to ask for a channel.

Empty and null results

Situation	What it means
`GET /api/v0/transcripts` returns no transcripts	Nothing matched in the window. A `callsign` we have never heard also returns an empty list, not an error. An unknown `facility_id`, `airline_id`, or `atc_channel_id`, or an unavailable channel, returns `400` instead.
Flight status `status` is `null`	The flight had no substantive communication on available channels in the hour before `at`. This includes a callsign we have never heard. Readbacks, check-ins, and sign-offs do not count.
Event search returns fewer than `limit` events	Fewer events matched well enough, or some matches were on channels outside your `facility_id` or `atc_channel_ids`. There is no next page.
PIREP search returns nothing	No PIREP in the window and area matched `q` well enough, or a recent PIREP is not searchable yet. A PIREP can take a few minutes after it is heard to become searchable.
Airport status `operations` fields are `null` and its lists are empty	We have no operations data for the airport newer than 30 minutes. `weather.metar` and `weather.taf` are `null` in that case too.

Results that change

Situation	What it means
An event has `updates`	The top-level `summary`, `happened_at`, and `callsigns` are the event as first reported. Later information is in `updates`, oldest first; the last update is the most complete.
A transcript’s `callsigns` changes	Callsign attribution can be corrected after a transmission is first processed. The live `transcripts` topic does not resend a transmission after a correction; fetch it again with Get transcript for the current attribution.
An airport observation disappears	The observation went 60 minutes without an update. That does not mean the situation ended. When a situation ends while it is still being tracked, its last update says so in `change`.
A flight status changes	A new substantive communication with the flight changed it. Use `status_at` to order statuses.

When a request succeeds but returns nothing

Check coverage

Find the facility in GET /api/v0/facilities and confirm that the channels you expect have is_available set to true.

Check the window

since and until are compared with received_at (transcripts) or happened_at (events and PIREPs), in UTC. Make sure the window covers when the traffic happened, and remember that the maximum window is 48 hours for transcripts and events and 6 hours for PIREPs. See Selecting data.

Remove filters

Run the request with only since, until, and facility_id. If transcripts come back, a callsign, airline_id, or atc_channel_ids filter excluded them. Callsigns are ICAO, e.g. UAL406, not UA406.

Broaden the search

For GET /api/v0/events and GET /api/v0/pireps, describe what you want in different words. Results are ranked by meaning, and weak matches are left out. For PIREPs, also try a larger radius_nm.

Contact support

If an available channel returns nothing for a window when you expect traffic, email support@enhancedradar.com with the request and its X-Request-ID response header.

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Core concepts

Guides

Interpret empty, null, and changing results

Coverage

Empty and null results

Results that change

When a request succeeds but returns nothing

​Coverage

​Empty and null results

​Results that change

​When a request succeeds but returns nothing

Coverage

Empty and null results

Results that change

When a request succeeds but returns nothing