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IFF/SSR Home Page

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Identification Friend or Foe/Secondary Surveillance Radar (IFF/SSR)

The Civil Aviation Authority’s Directorate of Airspace Policy (DAP) provides the focal point and Secretariat to the Cabinet Office sponsored National IFF/SSR Committee (NISC) which is responsible for the policy, operation and licensing of IFF/SSR interrogators in the UK, including ACAS I collision warning systems.

DAP also provides the focal point for the implementation of Mode S SSR in the UK and is responsible for the management of the UK SSR code allocation plan.


IFF/SSR Interrogators
Approval of Mode S SSR Interrogators
Approval of Mode A/C Interrogation Capability
Contact details

SSR Codes
Contact details

ICAO 24 bit Aircraft Addresses
ICAO 24 bit Aircraft Addresses
24-bit AAs and Aircraft Identification Reporting AIC 94/2004 (Yellow 151) superseded by AIC 101/2007 (Yellow 250)
Emergency Locator Transmitters (ELTs) AIC 57/2003 (Pink 55)