EASA SIB CE-10-22: Honeywell GNS Series Navigation Systems

What to do

Operators should avoid loading any approach or departure procedures listed in Table 3 of Honeywell's Service Information Letter D201003000024, as well as any procedures marked as Special Aircraft & Aircrew Authorization Required on charts. Procedures requiring RF leg capability should not be loaded into the affected GNS systems. Additional guidance is available from Honeywell's website and the referenced Service Information Letter. No specific compliance deadline is stated.

Summary

The FAA Special Airworthiness Information Bulletin SAIB: CE-10-22 addresses a software anomaly in Honeywell GNS Series Navigation Systems, specifically the GNS_XLS PRNAV (P/N 17960-0103-XXX), GNS_XLS Enhanced PRNAV (P/N 17960-0204-XXX), and GNS_XL PRNAV (P/N 18355-0102-0XXX). This anomaly affects RNAV procedures containing Radius-to-a-Fix (RF) legs, potentially causing the system to fail to capture and fly the curved RF path. The bulletin clarifies that this issue does not currently warrant an airworthiness directive under 14 CFR part 39.

What changed

This bulletin introduces awareness of a software anomaly in Honeywell GNS Series Navigation Systems that impacts the handling of RF legs in RNAV procedures. It does not impose mandatory actions but provides recommendations to avoid loading certain procedures that require RF leg capability. The FAA has completed its review and determined no unsafe condition exists that requires an airworthiness directive at this time.

Why it matters

This information is critical for aviation professionals operating aircraft equipped with Honeywell GNS Series Navigation Systems, as improper use of affected RNAV procedures could lead to navigation deviations. Operators and maintenance personnel must understand the limitations of these systems to ensure safe flight planning and compliance with navigation requirements. Awareness helps prevent potential navigation errors during approaches or departures involving RF legs.