Cessna 337 N143JB accident near Sylmar, California

Probable cause

The pilot’s loss of airplane control while troubleshooting a landing gear issue, which resulted in an aerodynamic stall/spin at an altitude too low to recover. Contributing to the accident was the pilot’s impairment from alcohol consumption.

NTSB analysis

Shortly after takeoff, the pilot reported to the tower controller that he was not able to retract the airplane’s landing gear and requested to circle the airport at 2,500 ft. The airplane climbed to and remained at about 2,000 ft for about 2 minutes before entering a descent that continued until ground contact. Witnesses saw the airplane descending in a steep, nose-down attitude, and a surveillance video showed the airplane rotating in a nose-down attitude as it collided with terrain.

Examination of the airframe and engines revealed no preaccident mechanical malfunctions or failures that would have precluded normal operation.

Toxicology testing of the pilot revealed 65 (mg/dL, mg/hg) ethanol in blood, 133 (mg/dL, mg/hg) ethanol in urine, and 10 (mg/dL, mg/hg) glucose in vitreous fluid. The ethanol production was not attributed to putrefaction. Based on the levels found and their distribution, it is likely that the pilot’s blood ethanol concentrations were around 0.12 gm/dL.

It is likely that, while trying to troubleshoot the landing gear issue, the pilot allowed the airplane to slow and exceed its critical angle of attack. The airplane subsequently entered a spin from which the pilot was not able to recover. Given the levels of ethanol found in toxicology testing, the pilot would have likely experienced degradation of judgment, reasoning, and coordination that would have affected his ability to safely manage the airplane, and it is likely that his impairment due to alcohol consumption contributed to his loss of control.

Text from the NTSB. Open the NTSB docket for WPR22FA160 for the full record.