Does CS-STAN allow the installation of Garmin GNS devices?
The main functionality of these devices is COM/NAV/GPS. CS-SC052b (GNSS equipment) allows the combination with CS-SC001 (COM) and CS-SC056 (NAV). Thus its installation can be considered eligible for CS-STAN. However, the limitations of CS-SC52b have to be respected. In particular, any connection with an autopilot is not permitted, since such use would go beyond the limitation to situational awareness only.
Does CS-STAN allow the installation of Garmin GTN devices?
The functionality of the Garmin GTN series exceeds the one covered by CS-SC052b and thus its installation is not eligible for CS-STAN.
Garmin is holding an STC with a comprehensive AML for the installation of the GTN series. In cases where a European type is not listed on that AML, due to the absence of a FAA TC, the process of a minor modification or Form 134 could be used to extend the applicability of the STC, if agreed by EASA.
Does CS-STAN allow the installation of digital multifunction engine monitoring devices (e.g. EDM 900)?
CS-SC201a explicitly excludes the installation of digital multifunction devices.
Is there any AMC/GM related to CS-STAN?
AMC to M.A.801: Easy Access Rules for Continuing Airworthiness
AMC to 145.A.50 referring to M.A.801
GM to 21.A.90B and 431B referring to M.A.801