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Secondary surveillance radar

Secondary surveillance radar SSR and ADS-B


Circumstance Phraseology

Pilot transmission

1 To instruct setting of transponder

(a) Squawk (code) [and ident if required]
(b) [SQUAWK] (code) [AND IDENT if instructed by ATS]
(c) Squawk normal
To request:
Reselection of the assigned mode and code (d) Recycle [(mode)] (code)
Reselection of aircraft identification (e) RECYCLING [(mode)] (code)
Confirmation of Mode A (f) Re-enter Mode S (or ADS-B) aircraft identification
Code selection (g) Confirm squawk (code)
Operation of the ident feature (h) SQUAWKING (code)
Temporary suspension of transponder operation (i) Squawk ident
(j) Transmit ADS-B ident
(k) Squawk standby [transmit ADS-B only]
Emergency code selection termination of SSR transponder or ADS-B transmitter operation (l) Squawk mayday
Transmission of pressure altitude (m) Stop squawk [transmit ADS-B only]
(n) Stop ADS-B transmission [squawk (code) only]
Pressure setting check and confirmation of level (o) Squawk charlie
Termination of pressure altitude transmission because of faulty operation (p) Transmit ADS-B altitude
(q) Check altimeter setting and confirm level
(r) Stop squawk charlie, wrong indication
Altitude check confirmation of ADS-B operation (s) Stop ADS-B altitude transmission [(wrong indication, or reason)]
Change to secondary transponder (t) Verify [level] (level)
(u) ADS-B transmissions not received, confirm ADS-B operational
(v) Select secondary transponder
2 Advice or traffic level
Where the pressure altitude derived level information has not been verified
(a) Unverified level (level)
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