Transponder codes every pilot must know
The four reserved squawk codes, how to remember them, and when to press IDENT.
Your transponder answers radar with a four-digit code (a "squawk") and, in Mode C or S, your altitude. Most of the time ATC assigns your code. A few codes are reserved, and every pilot is expected to know them cold.
The transponder codes every pilot must know
| Code | Meaning | Memory trick |
|---|---|---|
| 1200 | VFR flight, not receiving an assigned code (U.S.) | The default VFR code |
| 7500 | Unlawful interference (hijacking) | Seven-five, taken alive |
| 7600 | Lost communications | Seven-six, radio needs a fix |
| 7700 | Emergency | Seven-seven, going to heaven |
Source: FAA AIM 4-1-20 and AIM 6-2-2. VFR codes differ outside the U.S. (7000 is common in Europe), so check local rules.
What IDENT does
Pressing IDENT makes your target stand out on the controller's screen for a few seconds. Only press it when ATC says "squawk ident" or "ident."
Changing codes without setting off alarms
When you change codes, avoid passing through 7500, 7600 or 7700 on the way. Many modern transponders let you type the code directly, which avoids the problem.
Radio Trainer
Practice ATC calls and readbacks
Open →Light gun signals
What the tower shows you when your radio is out
Open →Common questions
What does squawk 7700 mean?
Emergency. Set it when you have an emergency and are not already talking to ATC on an assigned code.
What is the VFR transponder code in the U.S.?
1200, unless ATC assigns you a different code.
What code do I use if my radio fails?
7600, for lost communications.
Sources, review & change history
- Published
- Oct 26, 2026
- Review status
- Written from the FAA sources linked in the text. Not yet re-checked line by line or reviewed by a flight instructor.
- Changes
- Oct 26, 2026: first published.
Study aid only. Your instructor, current 14 CFR and the FAA's handbooks and ACS have the final word.