Accident History
On the evening of February 8, 2019, at approximately 2010 Pacific standard time, a Mooney M20F airplane, registration N3270F, was destroyed when it impacted terrain near Diablo, California. The airplane had departed Hayward Executive Airport at 2003, heading northeast at an altitude of about 2,800 ft mean sea level (msl). Radar contact was lost at 2010 near the accident site. The next day, hikers located the wreckage about 1,000 ft below and 3/4 mile southwest of the summit of Mount Diablo. On the mountain, state park officers at different elevations reported fog, rain, and wind. The superintendent, who lived on the mountain, heard a low-flying airplane with a loud engine at the time of the accident, noting low altitude, wind, and clouds. A visitor center with a red light and a 300-ft tower with obstacle lights were near the summit.
Pilot Information
The pilot held a student pilot certificate and had logged 57.1 total flight hours. He had not received an endorsement for solo night flight or for cross-country flight on the intended route.
Aircraft Information
The two-seat, low-wing Mooney M20F was manufactured in 1967 and powered by a Lycoming O-360, 180-horsepower engine. No current airframe or engine logbooks were located.
Weather Conditions
Automated weather observations from Buchanan Field Airport, about 9 miles north-northwest, at 1953 reported wind from 020° at 6 knots, 3 miles visibility in moderate rain and mist, scattered clouds at 600 ft, broken ceiling at 1,300 ft, overcast at 2,800 ft, temperature 8°C, dew point 6°C. At 2014, conditions were calm, 5 miles visibility, clear sky, temperature 11°C, dew point 9°C. A low-pressure system with an occluded front was producing widespread clouds and precipitation. No severe weather alerts were in effect, but AIRMETs for mountain obscuration and moderate icing were current. Winds aloft at 2,900 ft msl were from 150° at 20 knots. The moon was 12° above the horizon with 16% illumination. The pilot did not contact flight services.
Wreckage and Impact
The airplane impacted the side of Mount Diablo at an elevation of about 2,846 ft msl. Debris spread over 100 ft, with the first point of contact showing disturbed dirt and broken vegetation. The airplane came to rest upright on a 30° slope, with a post-impact fire primarily in the cabin area. The fuselage lay on a magnetic heading of 113°. The left wing remained attached; the right wing separated but remained near the wreckage. The empennage separated about 3 ft from the horizontal stabilizer leading edge. The right wing outboard section was bent 90°; leading edge crushing was noted. Fuel tanks were breached and empty. Flight control continuity was established. The engine remained attached but bent 45° to the right. The two-bladed propeller separated; one blade showed leading-edge erosion. Examination of the engine revealed internal continuity, compression, spark from both magnetos, and an intact vacuum pump; no anomalies were found to preclude normal operation.
Medical Examination
An autopsy determined the pilot's cause of death as multiple blunt force injuries. Toxicological testing was negative for carbon monoxide, ethanol, and cyanide. Phentermine, a prescription amphetamine-class anti-obesity medication, was detected in blood and urine at 772 ng/mL. The medication can be misused for performance enhancement and fatigue relief.