Accident Details
A flight instructor, who also owns the aircraft, was providing flight instruction to his daughter in a Cessna 150F equipped with floats. The instructor was demonstrating an approach-to-landing stall at approximately 2,000 feet mean sea level with 20 degrees of flaps deployed. During the stall, the student pilot applied cross-control inputs, causing the left wing to drop and the airplane to enter an uncommanded inverted left spin. The instructor regained upright flight at about 300 feet above ground level by increasing engine power. During the recovery, the airplane descended in a nose-down attitude and struck the ground.
Aircraft Information
The Cessna 150F had been modified with a 160-horsepower engine and fixed floats. The aircraft qualified for float installation when the previous owner/mechanic designated it as a Cessna 150G. Configuration changes included different propellers, propeller spacers, larger wheels and tires, and a heavier nose wheel strut assembly. As a floatplane, the airplane was required to be operated in the normal category, and intentional spins were prohibited.
Pilot and Operational Factors
The instructor reported that no data was available to him about the consequences or recovery techniques for an inadvertent spin. A center of gravity calculation for the accident flight placed the airplane within approved weight and balance limits. Toxicological analysis of the pilot's samples revealed the presence of an over-the-counter antihistamine and a prescription anti-depression medication.