Squawk 1000 is a code sent via the transponder of an aircraft, alerting Air Traffic Control to its current location. According to the official list of transponder codes from the Federal Aviation Administration, it means different things depending on where you are located when you send it:
- In the US, Squawk 1000 is a code used solely by those piloting ADS-B aircraft to inhibit Mode 3A transmittance; it can also be used for non-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2, as well as in oceanic airspace, unless another code has been assigned by Air Traffic Control
- In Canada, Squawk 1000 is a code that refers to an Instrument Flight Rules (IFR) flight below altitudes of 18,000’ when no other code has been applied
- In Europe, Squawk 1000 is a code that refers to IFR GAT flights operating in designated Mode S Airspace