As previously mentioned, EASA have now published CS-STAN Issue 3 which contains numerous aircraft standard changes that may now be implemented with simplified paperwork.

Of particular interest is the long hoped for simplification of the process to install ADS-B Out in EASA CofA aircraft, including the ability to connect a non-certified GPS (GNSS) as the position source for a Mode S ES transponder, provided that the transponder manufacturer has explicitly stated compatibility.

The new CS-STAN Issue 3 is available here:

Within the document, see:

CS-SC004a — Installation of antennas

CS-SC005a — Installation of an ADS-B OUT system combined with a transponder system

CS-SC052c — Installation of VFR GNSS equipment


Here is an extract from CS-SC005a:

Standard Change CS-SC005a
1. Purpose
This SC is for the installation of ADS-B OUT systems. This SC allows the embodiment of different configurations for the voluntary transmission of ADS-B data (e.g. GPS position and velocity).

This SC addresses three cases:
— Configuration 1: an ADS-B OUT system that conforms to AMC 20-244;
— Configuration 2: an ADS-B OUT system with an ETSO-C199() GNSS position source;
— Configuration 3: an ADS-B OUT system with a GNSS position source that is not approved.

Note: The aircraft identified in the applicability/eligibility section of this SC do not need to comply with Commission Implementing Regulation (EU) No 1207/2011 or its later amendments. Consequently, they do not need to satisfy the requirements set by CS-ACNS Subpart D Section 4 ‘1090 MHz Extended Squitter ADS-B Out’.

The likelihood of erroneous data being transmitted to ADS-B ground stations and to other aircraft is defined by quality indicators.
— Configuration 1 installation provides quality indicators according to the principles that are defined in AMC 20-24 while controlling the latency through a direct connection between the transponder and the GNSS position source.
— Configuration 2 installation provides quality indicators that are defined in ETSO-C199.
— Configuration 3 sets the quality indicators to zero (0). Operators of aeroplanes fitted with a configuration 3 installation are expected to use the system for traffic awareness only. Equipment emitting with quality indicators that are set to 0 might not be seen by other aircraft systems or by ATC.