Transponder (Squawk) Codes
A transponder “squawk” is the four-digit (octal) code ATC assigns or a pilot selects. A handful are reserved worldwide for emergencies and special operations — memorise the three emergency codes first.
Emergency & special codes (memorise these)
| Code | Meaning |
|---|---|
| 7500 | Unlawful interference (hijack) |
| 7600 | Lost communications (radio failure) |
| 7700 | Emergency (any nature) |
| 7777 | Military interceptor operations (do not use) |
Memory aid: “75 taken alive, 76 won’t fix, 77 going to heaven.”
VFR & general codes
| Code | Meaning / region |
|---|---|
| 1200 | VFR (United States), all altitudes |
| 7000 | VFR conspicuity (ICAO / Europe) when no code assigned |
| 1202 | Gliders, not in contact with ATC (US) |
| 1255 | Firefighting aircraft (US) |
| 0000 | Reserved / SSR malfunction (do not select) |
Frequently asked questions
What is squawk 7700?
7700 is the universal emergency transponder code. Setting it alerts every ATC facility that you have an emergency, even if you cannot reach them on the radio.
What code do I squawk for VFR in the US?
Squawk 1200 for VFR flight in the United States unless ATC assigns a discrete code. In ICAO/European airspace the equivalent VFR conspicuity code is 7000.
Reference only — verify against the current FAA Aeronautical Information Manual (AIM) and regulations before flight. More quick reference.