What happened
The pilot initiated takeoff into a headwind ranging from 20 to 25 mph. After climbing out, the pilot turned onto the downwind leg of the traffic pattern and attempted to attach a banner intended for towing. Upon securing the banner, full power was applied to maintain altitude, and the aircraft was leveled off.
Shortly after this maneuver, the airplane began to vibrate significantly while simultaneously losing engine power. This condition persisted without recovery until the aircraft impacted the ground. Eyewitnesses observed the airplane stall during the incident. Later, when speaking with an insurance adjuster, the pilot described the vibration as a classic initiation of a stall.
The investigation
The investigation focused on the mechanical state of the aircraft and the sequence of events leading to the impact. Examination revealed that the engine lost power following the application of full power during the banner attachment phase. No evidence suggested a pre-existing mechanical failure prior to the maneuver.
Findings
Several factors contributed to the accident. The pilot's decision to attempt banner attachment while in a low-energy state near the ground was critical. The resulting vibration and loss of power were identified as stall characteristics. The aircraft entered an unrecoverable stall condition during the critical phase of flight.