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20-138C - Airworthiness Approval of Positioning and Navigation Systems (Cancelled)

Cancellation Notes
AC 20-138D
Date Cancelled
March 28, 2014
Date Issued
May 08, 2012
Responsible Office
AIR-130,  Aviation Safety - Aircraft Certification Service, Aircraft Engineering Division

This advisory circular (AC) provides guidance material for the airworthiness approval of installed positioning and navigation equipment. This revision corrects minor errors, clarifies guidance, adds a frequently asked question section, and updates technical standard order (TSO) information. Major changes in this AC reflect TSO-C129a cancellation; updated guidance related to TSO-C115c; clarifying information in paragraphs 14-6.8 and 14-8.13 for the ground proximity warning system/terrain awareness and warning system (GPWS/TAWS) glideslope alerting function, and adding additional testing procedures in Appendix 4 for global navigation satellite systems (GNSS) that support automatic dependent surveillance - broadcast (ADS-B).