EASA SIB CE-16-12
Garmin G500/G600 IFDS — Honeywell KFC275/KFC325 AP Systems — STC SA02153LA-D
Summary
The Garmin G500/G600 IFDS — Honeywell KFC275/KFC325 AP Systems — STC SA02153LA-D is a Special Airworthiness Information Bulletin (SAIB CE-16-12) issued by the FAA on January 25, 2016. It addresses an airworthiness concern involving certain Honeywell KFC 275 and KFC 325 autopilot systems interfaced with Garmin G500/G600 Integrated Flight Deck Systems, specifically installed on aircraft such as the Socata TBM 700/850 and Pilatus PC-12. The bulletin highlights potential inappropriate pitch commands and unintentional autopilot mode disengagement due to signal translation errors in these configurations.
What Changed
This bulletin identifies an intermittent signal processing error in the Garmin GAD 43e unit when used with Honeywell KFC 275 or KFC 325 autopilots in G500/G600 configurations. It introduces recommendations for a software upgrade via Garmin Mandatory Service Bulletins No. 1570 and 1571 to correct the issue. The bulletin does not mandate regulatory action but provides guidance to mitigate the concern.
Why It Matters
This information is critical for operators and maintenance personnel of affected aircraft to prevent unexpected autopilot behavior that could compromise flight safety. Understanding the issue helps pilots monitor autopilot performance and take corrective action if inappropriate pitch commands or mode disengagement occur. Compliance teams benefit from knowing the recommended software update to maintain airworthiness and operational reliability.
What To Do
Operators should monitor autopilot and flight director functions closely and disengage autopilot immediately if inappropriate pitching occurs. Until the software fix is installed, pilots are advised to minimize use of vertical speed and altitude capture modes, using pitch attitude hold or indicated airspeed modes instead. The FAA recommends contacting Garmin dealers to implement the GAD 43e Expansion Board Software Version 2.31 as detailed in Garmin Service Bulletins 1570 and 1571.