This category includes heavy and fast general aviation aircraft fulfilling one of the following criteria :
Airspeed is directly affecting the ability to see and avoid. A combination of low antenna range and high closing speeds can lead to a very short time window for the pilots to react.
Therefore, the technology recommendation is split into aircraft with cruising speeds up to 140 knots TAS and aircraft with even higher cruising speeds. When applying for special financing, the aircraft owner is required to indicate their aircraft’s typical cruise speed in knots true airspeed (KTAS).
The Mode S transponders without ADS-B are widely adopted and is the minimum equipment in a CTR, TMA or class E airspace at and above 7’000ft MSL, or class G when flying below VMC conditions (refer to VRVL Art. 29). Of course, an existing Mode S transponder should be kept, and we consider it an econspicuity device. The recommendation below focuses on the interoperability with other aircraft categories and technologies.
A Mode S transponder without ADS-B out should ideally be supplemented by one of the recommended technologies, because it will not always be electronically visible (e.g. when there is no ground radar or TCAS interrogation).
Recommended due to the inherent benefits of a certified installation (e.g. known reliability, range, diversity). Ensures interoperability with traffic warning systems in other motor-powered aircraft. This solution works well even at the highest aircraft speeds. The additional ADS-L receiver is needed to sense other traffic.
Recommended for traffic information integration into certified avionics, ideally with the ability to receive traffic information via ADS-B, Mode S and FLARM. A traffic warning system might only receive traffic. Therefore, we recommend a combination with ADS-B out or ADS-L out to transmit the sender position.
Please note that such a system might not always detect other traffic with Mode S transponders. Mode S transponders without ADS-B will only transmit data when replying to interrogations from a ground radar or a TCAS The other aircraft’s transponder replies in the same mode as the interrogation. If a ground radar only interrogates Mode A/C (e.g. Lukmanier Pass), the Mode S transponder will reply in Mode A/C and not show on certain devices.
Last modification 26.06.2025
