Aircraft: Grumman American. Injuries: 2 Fatal. Location: Corona, Calif. Aircraft damage: Destroyed.
What reportedly happened: The Grumman was flying in mountainous terrain on what was supposed to be an introductory instructional flight.
According to a witness on the ground, as the plane approached the foothills, it entered a series of turns while flying unusually low along the ridge line. As it began to roll out of a turn, the wings started to rock from side to side, and the plane then immediately descended nose-down into the ground and caught fire.
Analysis of the radar data revealed that, in the final turn, the airplane was flying at a speed of about 77 knots with a turn radius of about 400 feet. To achieve the turn radius observed would have required a bank angle between 50° and 60° with an associated increase in load factor that would have caused the airplane’s stall speed to match or exceed its airspeed. The airplane’s design was such that uncoordinated flight control input close to stall speed could result in an unrecoverable spin.
The investigation did not reveal any mechanical malfunctions or failures that would have precluded normal operation.
Probable cause: An aggressive flight maneuver performed by the pilot during low altitude flight, which resulted in an aerodynamic stall.
NTSB Identification: WPR11FA344
This July 2011 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.