The lack of manufacturer written advice, limitations, cautions, or warnings (written or aural) about autopilot response to manual pilot control inputs meant that pilots may be unaware that their actions can lead to significant out of trim situations, and associated aircraft control issues.
The proposed safety action will increase pilot awareness for those pilots with access to the Pilot Safety and Warning Supplements. However, the ATSB believes that wider dissemination of the issue is possible. For that reason, while the ATSB recommendation will be closed, it is considered only partially addressed.
The ATSB recommends that Cessna Aircraft Company, in conjunction with Garmin, implement changes to their operations manuals so that all aircraft types fitted with their autopilots have the limitations, cautions and warnings applied consistently.
In response to the issued safety recommendation, Textron Aviation issued a revision to the Pilot Safety and Warning Supplement that is provided with every Cessna aircraft propeller product Owner’s Manual and Pilot’s Operating Handbook. The Supplement is also available through the manufacturer’s Customer Service website. The revised document contained a section on Autopilots and Electric Trim Systems that included a warning that overriding an engaged autopilot system will cause the trim system to oppose the pilot’s input and result in an out of trim condition.
The ATSB recognises the safety action that Textron (Cessna Aircraft Company) has implemented to improve pilot awareness of the issues relating to the manual manipulation of the flight controls with the autopilot on. However, the Pilot Safety and Warning Supplements will not be readily available to vast majority of Cessna pilots’ who have not purchased a new aircraft or requested a new supplement.
