Aircraft Accident/Incident Report

Anchorage, Alaska 99502
Thursday, July 20, 2000 12:30 AKD

According to the first pilot, a flight instructor and owner of the accident airplane, he was providing flight instruction to his daughter in a float-equipped Cessna 150F airplane. He was demonstrating an approach to landing stall about 2,000 feet mean sea level. The airplane was configured with 20 degrees of flaps. When the airplane stalled, the student pilot cross-controlled the airplane. The left wing dropped and the airplane entered an uncommanded, inverted left spin. The instructor was able to recover the airplane to an upright attitude about 300 feet above the ground by adding engine power. The airplane continued to descend in a nose down attitude during the recovery, and struck the ground. The airplane had numerous modifications, including a 160 horsepower engine. The airplane had fixed floats installed, and qualified for the float installation when the previous owner/mechanic designated that the airplane be operated as a Cessna 150G. Changes from wheels to floats resulted in several configuration changes including propellers, and propeller spacers, larger wheels and tires, and the use of a heavier than normal nose wheel strut assembly. As a floatplane, the airplane was required to be operated in the normal category, with intentional spins prohibited. No data was available to the pilot about the consequences, or recovery techniques for an inadvertent spin. A center of gravity calculation of the accident flight placed the airplane within weight and balance limits. The presence of an over-the-counter antihistamine, and a prescription anti-depression medication, were found in the pilot's toxicological samples.

The failure of the pilot-in-command (CFI) to adequately supervise the instructional flight. Factors in the accident were an inadvertent spin entry by the student, and the pilot-in-command's failure to utilize adequate altitude for a stall demonstration.