Description

Transponder equipage is mandatory for flights conducted as General Air Traffic (GAT) under Instrument Flight Rules (IFR) in the SES airspace which is part of the ICAO EUR region. In addition to these provisions, many European States also impose requirements for Visual Flight Rules (VFR) flights in some designated airspaces.

There are no specific provisions for the equippage of state aircraft. However, if state aircraft operate as GAT under IFR, they are subject to the same requiremets as civil aircraft.

The transponder requirements are defined in Regulation 2023/1770 and include:

• all aircraft flying as GAT/IFR must be equipped with serviceable SSR transponders that have the capabilities for airborne Mode S Elementary Surveillance. These transponders must operate with a 24-bit ICAO aircraft address that corresponds to the registration assigned to the aircraft.
• aircraft with MTOM greater than 5700 kg or with TAS greater than 250 kt, with an individual certificate of airworthiness first issued on or after 7 June 1995, must also have the capabilities for 1090 MHz Extended Squitter ADS-B Out (exceptions exist)
• fixed-wing aircraft with MTOM greater than 5700 kg or with TAS greater than 250 kt, with an individual certificate of airworthiness first issued on or after 7 June 1995, must also have the capabilities for airborne Mode S Enhanced Surveillance (exceptions exist).

The exceptions mentioned above apply to:

• aircraft being flown to undergo maintenance
• aircraft being flown for export
• aircraft whose operation will cease by 31 October 2025

Aircraft with inoperative transponders where the 1090 MHz Extended Squitter ADS-B Out or the Mode S Enhances Surveillace capabilities are affected, can be operated for a maximum of 3 consecutive days.

Further Reading

• Policy for radio mandatory zone and transponder mandatory zone, UK CAA, 14 August 2015
• Guidance Material for Mode S-Specific Protocol Application Avionics by R.D. Grappel and R.T. Wiken, MIT Lincoln Laboratory for the USAF, 2007
• Minimum Operational Performance Standards for 1090 MHz ADS-B and TIS-B, EUROCAE ED-102A / RTCA DO260B, 2009
• Preliminary safety case for enhanced ATS in NRA using ADS-B, EUROCONTROL