Amateur-built ULTIMATE AERO 10-200 N827D accident near Saint Albans, Vermont

Probable cause

The propeller blade’s failure due to fatigue cracks that initiated from pitch change pin attachment holes that had been drilled too deep during manufacture.

NTSB analysis

The commercial pilot was conducting a local personal flight in his experimental amateur-built aerobatic airplane. The pilot reported that, about 10 minutes after takeoff and while climbing to 3,000 ft mean sea level, there was a sudden loud bang/shudder. The canopy then shattered, the engine experienced a total loss of power, and the airplane entered a spin that the pilot could not arrest. The pilot subsequently decided to egress the airplane via parachute. The airplane subsequently struck terrain and was consumed by a postimpact fire.

Examination of the propeller revealed that one of the two propeller blades had separated from the two-bladed, constant-speed propeller's hub. The propeller blade had fractured due to fatigue cracks that initiated from pitch change pin attachment holes that were drilled too deep during manufacture. Subsequent to the accident, the manufacturer recognized that the hole depth varied and instituted quality control measures. At the time of the accident, the propeller had been operated for about 260 hours.

Text from the NTSB. Open the NTSB docket for ERA14LA202 for the full record.