Cessna 172M N9932V accident near Greenville, Maine

Probable cause

The pilot's failure to maintain adequate airspeed while manuevering at low altitude, which resulted in an aerodynamic stall/spin and subsequent impact with terrain.

NTSB analysis

On the morning of the accident, the airplane was observed circling at low altitude in a left turn about 1 mile southwest of the departure airport with the pilot visibly waving at people on the ground. During the third and last circle, the airplane pitched nose up, decelerated, then pitched nose down steeply and descended toward the ground. The airplane then rotated to the left with its nose still pointed down, turned about 180 degrees from its original direction of travel, then disappeared from view. Moments later the sound of an impact was heard.

Postaccident examination of the airplane and engine did not reveal any evidence of preimpact malfunctions or failures that would have precluded normal operation.

Toxicological testing of the pilot revealed the presence of carbon monoxide in his blood; however, the carbon monoxide level was consistent with a heavy smoking habit. Tetrahydrocannabinol (THC) (marijuana) was also detected in his lungs but not in his blood, and THC corboxylic acid was detected in his urine, liver, and lungs. However, the THC findings were consistent with a remote usage of marijuana (that is, not immediately before flight), and the absence of THC in his blood indicated that the pilot was likely not impaired.

Download of a portable GPS discovered in the wreckage confirmed the witness' observations of the airplane’s flightpath and that the pilot was maneuvering at low altitude (less than 500 feet above ground level) when the airplane decelerated below its aerodynamic stall speed and entered a spin. Review of manufacturer's published data indicated that altitude loss during a stall recovery could be as much as 250 feet, and 1,000 feet of altitude loss for a one-turn spin and recovery could be expected.

Text from the NTSB. Open the NTSB docket for ERA11FA493 for the full record.