Grumman American Avn. Corp. AA-5A N26676 accident near Homosassa, Florida

Probable cause

A partial loss of engine power for reasons that could not be determined because engine examination did not reveal any anomalies that would have precluded normal operation.

NTSB analysis

The pilot reported that, when the airplane was in cruise flight at 1,500 ft above ground level, the engine began to intermittently run roughly. The pilot initially applied carburetor heat, but he then turned it off because he did not observe the engine power improve. The engine power loss became more consistent, and the airplane was unable to maintain altitude. The pilot attempted to divert to a nearby airport while the pilot-rated passenger tried to restore engine power; however, the airport was 5 miles away, and the airplane could not glide that far at its altitude. The pilot then attempted to perform a forced landing to a field. During the approach, the pilot-rated passenger took control of the airplane, which subsequently collided with power lines, impacted the field, and then came to rest upright.

Examination of the wreckage revealed that 25 gallons of fuel remained onboard. Examination of the engine did not reveal any preimpact mechanical malfunctions. When the propeller was rotated by hand, camshaft, crankshaft, and valve train continuity were confirmed, and thumb compression was attained on all cylinders. The magnetos produced spark at all of the leads, and no obstructions were observed in the carburetor venturi. The temperature and dew point at the time of the accident were conducive to the accumulation of serious icing at glide power; however, the engine was at cruise power when the power loss occurred.

Text from the NTSB. Open the NTSB docket for ERA14LA451 for the full record.