Squawk Codes – 7000, 7500, 7600, 7700
Definition
A squawk code is a four-digit number set into the aircraft’s transponder, allowing ATC to identify and monitor the aircraft on radar. These codes are assigned by ATC or pre-assigned in flight plans and help controllers correlate radio callsigns with radar returns.
Format and Range
- Four digits, using only numbers from 0 to 7
- Example: 7000, 1234, 4520
- Codes are set using transponder dials or digital avionics
- The code is transmitted automatically once the transponder is active
Standard Phraseology
- “Squawk 7000” → Set code 7000
- “Squawk standby” → Stop transmitting temporarily
- “Squawk ident” → Press IDENT button to flash on radar
- “Reset squawk xxxx” → Re-enter code due to incorrect data or loss of radar contact
- “Confirm squawk” → ATC verifying the code you’re transmitting
Transponder Modes
| Mode | Function |
|---|---|
| OFF | Transponder is off |
| STBY | Standby (no transmission) |
| ON (Mode A) | Transmits identity code only |
| ALT (Mode C) | Transmits code and altitude |
| Mode S | Enhanced: identity, altitude, and aircraft data (e.g. callsign, heading) |
Special Purpose Squawk Codes
| Code | Meaning | Used when... |
|---|---|---|
| 7000 | VFR standard code (in many European countries) | Flying VFR without ATC radar service |
| 7500 | Hijack | Aircraft under unlawful interference |
| 7600 | Radio failure | Lost communication capability |
| 7700 | Emergency | General emergency (medical, engine failure, etc.) |
| 0000 | Free balloon operations (in some countries) | Used for unpowered balloon flights |
Important: These codes must not be set by mistake — misuse can trigger major emergency responses.
When to Squawk
- When assigned by ATC
- Automatically via Mode S transponder (for flight plan correlation)
- 7000 when operating VFR without a discrete code
- Switch to 2000 when entering another FIR if no code was received (country-specific)
Example Scenario
ATC: “D-EABC, squawk 4725”
Pilot: “Squawk 4725, D-EABC”
(Pilot sets 4725 and confirms transmission with IDENT if requested)
IDENT Function
When instructed to “Squawk Ident”, the pilot presses the IDENT button. This causes the aircraft’s radar return to highlight or flash on the ATC radar screen, helping the controller quickly locate the aircraft.
Tip
Always verify the current code when switching frequencies. If in doubt, confirm with ATC using:
“Confirm squawk for D-EABC?”
