TECHNICAL SERVICE BULLETIN 062920C: Autopilot Servo Installation & Maintenance Manual for Cessna Models 172 F-S
Original Bulletin: June 29, 2020
PLEASE READ THIS BULLETIN IN ITS ENTIRETY BEFORE CONTACTING DYNON AVIONICS
Description
Dynon Avionics document, 103526-000 - Rev C - SkyView HDX Cert AP Servo Install Manual - Cessna 172F-S, contained incorrect information regarding pitch and roll servo bridle clamp installations. The document was made available in the Dynon Certified manual repository (www.dynon.aero/stcdocs) on 11/05/2019.
A new, corrected revision (Rev D) of the document replaced Rev C on 06/25/2020.
Applicability and Affected Equipment
If your Cessna 172 F-S had a Dynon autopilot installed in accordance with document, 103526-000 - Rev C - SkyView HDX Cert AP Servo Install Manual - Cessna 172F-S, then your aircraft is affected. These installations most likely took place between 11/05/2019 and 06/25/2020.
The pitch and roll servo installation procedures in the document incorrectly specify the bridle cable clamps be torqued to 20-25 inch-pounds (instead of the correct 35-40 inch-pounds).
Unaffected Equipment
Only Cessna 172 F-S Autopilots installed in accordance with the document, 103526-000 - Rev C - SkyView HDX Cert AP Servo Install Manual - Cessna 172F-S, are affected. If an installation was finalized before 11/05/2019, it is unaffected by this issue (as it predates the affected Rev C revision of the manual).
All other equipment is unaffected.
Interim Operating Recommendations
If your aircraft is affected, DO NOT use the autopilot until the installation has been inspected by qualified personnel in accordance with document, 103526-000 - Rev D - SkyView HDX Cert AP Servo Install Manual - Cessna 172F-S.
Solution
Have a certified technician torque the bridle cable clamp bolts to 35-40 inch-pounds on the servo bridle cable assemblies in accordance with the 103526-000 - Rev D - SkyView HDX Cert AP Servo Install Manual - Cessna 172F-S document. This document also provides information about accessing the pitch and roll servo bridle cable assemblies.
Time in Effect
This technical service bulletin is in effect indefinitely or until superseded by a future bulletin.