Clarifications on installation of an ADS-OUT system combined with a transponder system (CS-SC005a) – Portable units
The use of ADS-B portable units is not covered by CS-STAN.
Additionally, the usage of ADS-B portable units must be authorised by the National Aviation Authorities and by the Air Navigation Service Providers. Simultaneous ADS-B OUT transmissions from the same aircraft (e.g. installed + portable ADS-B OUT) has a negative impact on Air Traffic Services because it creates interference. Pilots and aircraft owners should make sure that an installed Mode S transponder does not broadcast ADS-B OUT parameters simultaneously with an allowed portable ADS-B OUT unit (e.g. as part of ADS-B trials organised by Air Navigation Service Providers). However, there is no restriction on the usage of an ADS-B IN only portable unit (reception of ADS-B transmissions).