On May 25, 2011, about 1030 eastern daylight time, a Cessna 152, N222UM, was standing with the engine operating when the flight instructor exited the airplane with a student pilot at the controls. The flight instructor was struck by the propeller and sustained serious injuries. The airplane was registered to and operated by University of Michigan Flyers Inc. under the provisions of 14 Code of Federal Regulations Part 91 as an instructional flight. Visual meteorological conditions prevailed at the time of the accident. The instructional flight began about 0800 and was to remain in the traffic pattern of Ann Arbor Regional Airport, Ann Arbor, Michigan.

The flight instructor stated she had four hours of sleep before arriving at the airport at 0620 to begin providing flight instruction for the student pilot's second supervised solo flight. She provided ground instruction to the student pilot while waiting for rain showers to clear the area. Once the weather cleared, they began the flight and performed takeoff and landings at the airport. Upon completion of the takeoffs and landings, they taxied to the ramp where the flight instructor exited the airplane with the engine operating. The flight instructor stated that instead of walking toward the rear of the airplane, as would normally be done to allow a student pilot to solo, the flight instructor walked toward her car, which was toward the front of the airplane. The flight instructor held her headset with its cords dangling in her left hand with her jacket and flight bag in her right hand. The headset cord was caught by the moving propeller, turning her into the propeller.

The flight instructor stated that the operator's flight instructors would typically have the airplane pointed in the direction that it was going to taxi in for a solo flight. Flight instructors would then exit toward the rear of the airplane with the engine operating. The flight instructor stated that the operator's post accident policy/procedure is to not allow passengers/personnel to enter and/or exit from aircraft with the engine operating.

Advisory Circular 91-42D, Hazards of Rotating Propeller and Helicopter Rotor Blades, section 8. Flight Personnel and Flight Instructors, states:

a. The engine of a fixed-wing aircraft or a helicopter should be shut down before boarding or deplaning passengers. This is the simplest method of avoiding accidents.

Cessna Pilot Safety and Warning Supplement, Potential Hazards, Propellers, states:

Pilots can be most effective in ensuring that his or her passengers arrive and depart the vicinity of the airplane safely by stopping the engine(s) completely at the time of loading and unloading, or by providing a definite means of keeping them clear of the propeller if it is left in motion.