Summary
This document proposes adopting a new airworthiness directive (AD) for the Trimble or FreeFlight Systems 2101 I/O Approach Plus global positioning system (GPS) navigation system (2101 I/O Approach Plus system). The AD would require a software upgrade for this system. This proposal is prompted by an incident that led to the discovery of several annunciation errors with the 2101 I/O Approach Plus system. The actions specified by the proposed AD are intended to prevent a pilot from making an unsafe decision based on erroneous information provided by the 2101 I/O Approach Plus system, which could result in loss of control of the aircraft.