Incident Overview
A student pilot was conducting a takeoff climb when an autopilot trim failure occurred. The pilot attempted to disengage the autopilot using the red autopilot disconnect button on the control yoke, but the attempt was unsuccessful.
Training and Compliance
According to the investigation, the student pilot had not received training on the autopilot system from the operator. A review of the pilot's training records confirmed this lack of instruction. Title 14 CFR Part 91.9 requires pilots to comply with operating limitations specified in the airplane flight manual. The flight manual for the Cessna 172S mandates that pilots commit to memory a four-step procedure for autopilot, autopilot trim, or electric trim malfunctions. The student pilot did not follow this written instruction.
Landing and Outcome
The failure to comply with the flight manual procedure led to a loss of aircraft control during landing. The airplane porpoised on the runway, resulting in a hard landing on the nose gear. Examination of the autopilot system, both before removal from the aircraft and at the factory, revealed no abnormalities.
Regulations and Findings
The incident highlights a deviation from regulatory compliance (14 CFR Part 91.9) and insufficient training on the autopilot system. The investigation found that the autopilot functioned normally when tested, indicating that the malfunction may have been related to pilot response or system interaction rather than a mechanical defect.