The Cessna 120-140 Association Forum

Just looking over the tailbeacon stuff. In the manual titled Instructions for Maintenance and Continued Airworthiness, Table 8.1 there is a requirement for Altitude Encoder Testing for VFR Operations and the requirement is every 12 Calendar months. Is this the same as the 2 year transponder check IAW 91.411, part 41, App E, Para (c)? Will this now be an annual check?

I think that it is the tailbeacon’s altitude encoder they are referring to and not the encoder used by the transponder.
You just use the app to check the date of last calibration of the tailbeacon to the plane.
Matt

Page 27 of this manual explains the annual check:

https://uavionix.com/downloads/tailbeac ... -Rev-B.pdf