Amateur-built 'S AIRCAM N420PF accident near Grass Valley, California

Probable cause

The pilot’s failure to maintain adequate airspeed and his exceedance of the airplane’s critical angle of attack, which resulted in an aerodynamic stall/spin at an altitude too low for recovery.

NTSB analysis

The pilot and passenger departed the airport to conduct a local flight. ADS-B data revealed that the flight was conducted at a low altitude that overflew areas of interest. The airplane was flying near the passenger’s property, at an altitude that witnesses estimated as about 100 ft or less above ground level (agl), and an airspeed estimated to be around 50 mph, but likely closer to the airplane’s published stall speed of 39 mph. The airplane exhibited a “wobble” and then entered an aerodynamic stall/spin and impacted open terrain in a nose-low attitude.

Postaccident examination of the airframe and engines revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The airframe damage, wreckage distribution and near-vertical impact were consistent with a stall/spin while still under engine power.

According to a witness, the pilot had a history of conducting low altitude flights in the accident airplane. Before the accident, the accident pilot told a fellow pilot that he did not fly above 500 ft agl. During the first months of ownership, the local airport manager received complaints about the pilot’s low-altitude flying.

The airplane’s Pilot’s Operating Handbook (POH) states that the airplane did not come equipped with a stall warning device and that stall indications were not easily recognizable. The POH also advised operators to not operate at low altitudes at airspeeds less than 50 knots and advised operators to stay at least 500 ft away from people and property.

Toxicology testing of the pilot indicated the presence of THC (tetrahydrocannabinol), the active compound in marijuana. There is no known relationship between tissue levels and impairment; therefore, whether the pilot's use of a potentially impairing substance contributed to the accident could not be determined.

Text from the NTSB. Open the NTSB docket for WPR23FA110 for the full record.