AC 20-138C - Airworthiness Approval of Positioning and Navigation Systems

Document Information

Date Issued: May 08, 2012
Responsible Office: AIR-130, Aviation Safety - Aircraft Certification Service, Aircraft Engineering Division
Description: 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).