Mooney M20E N5562Q accident near Skyforest, California

Probable cause

The pilot’s failure to establish the proper airspeed after departure and to maintain adequate clearance from a ridgeline in high-density and downdraft conditions and his subsequent exceedance of the airplane’s critical angle of attack, which resulted in an aerodynamic stall with insufficient altitude to recover. Contributing to the accident was the pilot’s inadequate preflight weight and balance calculations, which failed to take into account the gross weight, high-altitude conditions, and center of gravity limit.

NTSB analysis

The private pilot reported that, a few minutes after departure for a cross-country flight and as the airplane neared the top of a ridgeline, it encountered a downdraft, aerodynamically stalled, and then impacted terrain. One of the passengers reported hearing an aural tone, which was consistent with the stall warning horn, for several seconds before impact.

Weight and balance calculations determined that the airplane was loaded near its maximum gross weight and had exceeded the forward center of gravity limit, which would have increased the airplane's stall speed during the accident flight. The calculated density altitude was about 6,550 ft, which likely reduced the available power and affected the climb rate.

A video of the final moments of the accident flight showed the airplane about 25 ft above ground level when the airplane entered a high pitch attitude, followed immediately by a rapid descent, consistent with an aerodynamic stall. According to the pilot, the airplane was about 1,000 ft above terrain when it stalled; however, given the location of the camera and the pitch attitude that was observed, it is likely that the airplane was within about 50 ft of terrain as the airplane crested the ridgeline. The pilot should not have attempted to cross the ridgeline at such a low altitude; a higher altitude would have provided a clearance zone to avoid turbulence and downdrafts. The pilot's failure to cross at a higher altitude resulted in the airplane's encounter with a downdraft with insufficient altitude to recover from the stall.

The pilot reported that there was no evidence of any preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR18LA069 for the full record.