What happened
During a takeoff in calm water and light winds, the aircraft type exhibited a steep nose-high attitude and a sharp climb. Observers noted that the engine power remained at takeoff levels without transitioning to climb power. Approximately 200 feet above the water, the plane entered a steep left bank before rolling rapidly to the right and striking the water at a steep angle. There were no reported survivors.
Findings
Investigations revealed that the aircraft had been modified with a Short Take Off and Landing (STOL) kit. Certification testing for this modification had previously established that the kit removed aerodynamic warnings of an impending stall, necessitating the installation of an audible stall warning system. Furthermore, stability tests indicated that the aircraft was least stable during the climb phase when using takeoff flaps, and required the installation of a ventral fin and horizontal stabilizer finlets to maintain directional stability.
At the time of the accident, the aircraft was missing the required ventral fin. Additionally, the audible stall warning circuit breaker had been pulled, effectively disabling the warning system. Evidence suggested that pilots had been trained using a manufacturer marketing video that incorrectly claimed the stall warning was unnecessary in the United States, leading to a practice of routinely disabling the horn. Notably, the aircraft had undergone 14 FAA inspections over the preceding 29 months without any noted deficiency regarding the missing ventral fin.