Accident Overview
On August 22, 2018, about 1615 Pacific daylight time, a Champion 7KCAB, registration N1682G, was substantially damaged in an accident approximately 8 miles northwest of Descanso, California. The flight instructor (FI) and the pilot receiving instruction (PRI) sustained fatal injuries. The aircraft was operated by the FI under 14 CFR Part 91 as an instructional flight.
Flight Path and Radar Data
Radar data indicated the aircraft departed Gillespie Field Airport (SEE) in San Diego/El Cajon, California, and proceeded on a northeasterly heading, climbing to about 3,200 ft above ground level (agl) across rising terrain. About 15 minutes into the flight, the aircraft was observed in a slight left turn at about 2,400 ft agl, then entered a right 360° decreasing turn before dropping off radar. The last radar hit was approximately 1,500 ft above the accident site. A pilot who flew with the instructor earlier that day reported that the instructor mentioned a planned spin training flight for the afternoon.
Aircraft Information
Weight and balance calculations based on the airplane's documentation showed that at takeoff, the aircraft weighed 1,723 lbs, exceeding the maximum gross weight of 1,650 lbs by 73 lbs. This placed the aircraft outside both the normal and acrobatic category flight envelopes.
Wreckage and Impact
The wreckage came to rest in a wooded ravine at an elevation of 2,585 ft msl in a mountainous area. The debris field extended about 120 ft in length and 20 ft wide on a heading of 112° magnetic. The first identified point of contact (FIPC) was a small crater with a flat rubber seal containing green glass fragments, consistent with the right-wing tip navigation light, indicating right-wing-first impact. Further debris included a larger crater, wing panels, and the cabin door. The main wreckage was found 90 ft from the FIPC, with the left wing intact and the right wing severely damaged. The empennage remained intact, and flight control continuity was established to the cockpit, with the left rudder control cable showing overload signatures. The engine and propeller showed no evidence of preimpact anomalies.
Medical and Pathological Information
Autopsies of both occupants listed the cause of death as blunt trauma. The FI was noted to have moderate to severe atherosclerotic cardiovascular disease, including 75% narrowing of the left anterior descending coronary artery, with no evidence of acute coronary event. Toxicological testing detected ethanol in both occupants' cavity blood and muscle, but not in brain tissue; no common drugs were found. The ethanol levels were attributed possible postmortem production.