Accident Overview
An aircraft operating under an instrument flight plan in instrument meteorological conditions (IMC) was cleared for an instrument approach to South Lake Tahoe Airport. After departing the initial approach fix on the published transition to the final approach course, radar contact was lost at 11,400 feet. Subsequently, the aircraft was observed descending out of clouds and maneuvering erratically in visual meteorological conditions (VMC) until it impacted terrain with no apparent attempt to recover. All four occupants were killed.
Pilot Medical History
Medical records indicated the pilot had a history of hypertension, hyperlipidemia, and a recent loss of 41 pounds on a rigid weight loss program. The autopsy revealed severe arteriosclerosis. The pilot had been taking diazide intermittently for several years. Post-accident toxicology results were negative.
Investigation Findings
The circumstances of the accident, in combination with the pilot's severe diet, medical history, and postmortem examination results support the conclusion that the pilot became incapacitated in flight. The official probable cause was determined to be loss of control in flight due to incapacitation (other cardiovascular) of the pilot in command.