Low-altitude stall kills two

These October 2009 accident reports are provided by the National Transportation Safety Board. Published as an educational tool, they are intended to help pilots learn from the misfortunes of others.

Aircraft: Aeronca 7AC. Injuries: 2 Fatal. Location: Gaylord, Mich. Aircraft damage: Destroyed.

What reportedly happened: The 52-year-old private pilot, who held multi-engine instrument and seaplane ratings, had logged about 2,800 hours, with 60 hours flown with the preceding six months.

Two off-duty state police troopers witnessed the accident as they drove along an interstate highway. They stated that the airplane made several “abrupt” turns as low as 200 to 300 feet above the ground.

At one point, the “plane’s wings were dipping slightly back and forth, as well as the tail of the plane was swaying slightly from side to side; however, the plane remained level and did not appear erratic.” The airplane completed another “very abrupt” right turn when “the nose dropped straight down and the plane rolled to the right and corkscrewed into the ground.” The airplane hit a grassy area adjacent to the interstate.

A post-accident examination revealed damage to the flight control system was consistent with impact forces and emergency personnel’s recovery efforts. GPS track data indicated that the average groundspeed between the final data points was approximately 44 knots. Airspeed indicator markings denoted the flaps up and flaps down power-off stall speeds as 49 knots and 42 knots, respectively. Local winds were calm.

Probable cause: The pilot’s failure to maintain adequate airspeed during a low altitude turn resulting in an aerodynamic stall/spin and loss of control.

For more information: NTSB.gov NTSB Identification: CEN10LA031