Eglin Air Force Base Airport
Aircraft Accident/Incident Report

Valparaiso, Florida 32542
Thursday, June 23, 2011 4:44 CDT

During a night instructional flight, the private pilot under instruction attempted a 360-degree power off approach. The maneuver, which is also practiced as a simulated engine failure, involves a 360-degree change of direction to a preselected landing spot. The pattern is designed to be circular, but the turn may be shallowed, steepened, or discontinued at any point to adjust the accuracy of the flight path. Flaps and landing gear can also be used to control descent rate. The maneuver generally commences about 2,000 feet over the intended landing spot (high key), descends to a 180-degree position about 1,000 to 1,200 feet (downwind key, or low key), continues to a 90-degree position about 800 feet (base-leg key) with a turn to final at a minimum of 300 feet. Radar data revealed that the airplane commenced the maneuver about 2,000 feet over the runway, but arrived at a 180-degree position about 400 feet high, and at a 90-degree position about 500 feet high. It continued around the circuit still high, and approaching the runway, the flight instructor advised the controller that student training was in progress, right base for the “option.” After being cleared for the option, the airplane descended to 1,100 feet over the runway. It then began a right turn away from the runway and had descended to 900 feet when the instructor stated that they were doing another 360-degree circuit. There were no further transmissions from the airplane, but there were two more radar returns, one at 900 feet, and the last at 600 feet in the right turn. About that time, a number of witnesses heard the engine “sputter,” but then all witnesses subsequently heard the engine power up. They then saw the airplane descend at a steep angle and impact an aircraft parking apron, coming to a stop in about 600 feet. Because of a postcrash fire, not all engine items could be extensively examined. Those that could, did not reveal any engine anomalies, except that one fuel injector was found completely blocked, while another was partially blocked, most likely due to thermal effects from the fire. Propeller ground scars indicated power at the time of ground impact. The engine had over 2,380 hours of operation since its last overhaul, and another pilot reported that he had an engine failure while overflying an outlying airport about 12 months earlier, which maintenance personnel could not duplicate. During that failure, the engine did not sputter, and it could not be restarted, either in flight or on the ground until the following day. No subsequent engine operating anomalies were noted. Radar and wreckage path evidence indicated the likelihood that neither pilot adequately monitored the airplane’s airspeed, which resulted in a right-turning aerodynamic stall. One pilot then attempted a recovery by adding power; however, by the time he did so, there was insufficient altitude to avoid the ground. The reason for the pilots’ distraction from monitoring airspeed cannot be definitively determined; whether related to the power-off approach, the sputtering engine, or something altogether different. However, in all scenarios, it remained incumbent upon both pilots to ensure that proper airspeed was maintained, which they did not do.

The pilots’ failure to maintain airspeed, which resulted in an inadvertent, low altitude aerodynamic stall.