Champion 7KCAB N1682G accident near Descanso, California

Probable cause

The pilot's decision to enter a spin without sufficient altitude to recover. Also causal to the accident was the pilot's inadequate preflight weight and balance calculations, which placed the airplane outside the normal and acrobatic category flight envelope, effecting the spin and recovery characteristics.

NTSB analysis

The flight instructor and the pilot receiving instruction were conducting an instructional flight for spin training. About 15 minutes into the flight, the radar data showed the airplane in a slight left turn at about 2,400 ft agl, then enter a right 360o decreasing turn before dropping off radar. The last radar hit was about 1,500 ft above the accident site. The airplane's final maneuver and rapid descent are consistent with a spin entry.

The FAA Advisory Circular AC 61-67C, Stall and Spin Awareness Training, provides information that reports spin avoidance, incipient spins, actual spin entry, spin, and spin recovery techniques should be practiced from an altitude above 3,500 feet AGL.

Examination of the accident site revealed the airplane impacted terrain in a right wing and nose down attitude. Examination of the wreckage revealed no anomalies with the airframe or engine that would have precluded normal operation. Damage to the airplane's fuel tanks indicated that they contained fuel at the time of impact. Damage to the propeller revealed varying degrees of impact damage consistent with some degree of engine power at the time of impact.

According to the weight and balance calculations, the airplane exceeded its maximum gross weight at takeoff by 73 lbs and the center of gravity was outside the acrobatic flight envelope. This could have affected the spin and recovery characteristics and may have degraded or enhanced the spin maneuver. It was not determined if either pilot was aware of the weight and balance of the airplane.

Although the flight instructor had postmortem evidence of atherosclerotic disease that could pose a risk to flight safety, there was no evidence of an acute cardiac event. For both pilots, toxicology testing showed small amounts of ethanol in cavity blood and muscle, but not in brain tissue. Thus, it is likely that the ethanol is due to postmortem production and not consumption of ethanol prior to the flight.

Text from the NTSB. Open the NTSB docket for WPR18FA237 for the full record.