History of Flight
On December 17, 2012, about 1234 Pacific standard time, a Mooney M20F airplane, N9524M, was destroyed when it impacted terrain while maneuvering near Yosemite Valley, California. The airplane was registered to and operated by the pilot under 14 CFR Part 91. The private pilot, sole occupant, sustained fatal injuries. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated from Santa Ynez Airport (IZA), Santa Ynez, California, about 1027, with an intended destination of Mammoth Lakes, California.
A family member reported the airplane overdue that evening, and the FAA issued an ALNOT at 2309. No ELT signal was reported. Search operations by Civil Air Patrol and local authorities were suspended on December 21, 2012. The wreckage was located by a Yosemite National Park visitor on July 7, 2013, near Vogelsang Peak.
Radar data showed the flight flew northeast, ascending to about 8,500 feet msl, then to 14,500 feet, then 17,000 feet, before descending and performing descending 360-degree turns. The last radar target was about 12 miles west of the accident site at 9,800 feet msl.
Personnel Information
The pilot, age 68, held a private pilot certificate with airplane single-engine land and instrument ratings. A third-class medical was issued March 3, 2011. He reported 3,000 total flight hours; his logbook showed 3,033.8 hours, with only 0.2 hours in the previous 90 days. No actual or simulated instrument time was logged since April 2009.
Aircraft Information
The four-seat, low-wing, retractable-gear Mooney M20F, serial number 670101, was manufactured in 1966. It was powered by a Lycoming IO-360-A1A engine, rated at 180 horsepower, and a Hartzell adjustable pitch propeller. Airplane logbook records were not located.
Meteorological Information
An NTSB meteorologist prepared a factual report. The NWS Surface Analysis at 1300 showed a low pressure system over northern Idaho with a cold front extending into Nevada and California. A 6 to 9-hPa pressure gradient existed over eastern California and Nevada. The NWS radar mosaic at 1230 depicted precipitation over the Sierra Nevada near the accident site.
The upper air sounding at 1600 from Reno indicated a surface wind from 250 degrees at 24 knots, with a mean wind of 259 degrees at 68 knots through 18,000 feet. The wind profile was favorable for mountain wave activity, with a wave near 8,900 feet capable of producing severe turbulence and updrafts of 1,545 fpm.
GOES-15 visible imagery at 1230 showed thick overcast clouds over the accident site, with lenticular clouds downwind. WSR-88D radar at 1235 indicated echoes of 10-35 dBZ over the area, suggesting precipitation. An AIRMET was current for mountain obscuration and moderate turbulence below 18,000 feet. Mammoth Yosemite Airport reported wind 320 degrees at 8 knots gusting to 19 knots at 1235, with VFR conditions. Columbia Airport reported wind 160 degrees at 7 knots, visibility 1.5 miles, ceiling overcast at 400 feet. It was not determined if the pilot obtained a weather briefing.
Wreckage and Impact Information
National Park Service Rangers reported the airplane came to rest upright on the northern base of a 500-foot vertical rock slope at about 10,679 feet msl. All major components were present. Due to the remote location, NTSB representatives did not visit the site. The wreckage was recovered for examination.
Medical and Pathological Information
An autopsy on July 11, 2013, determined the cause of death as "Multiple injuries." The autopsy was limited by body condition; no internal organs were available. Toxicology testing was not performed due to putrefaction.
Tests and Research
An examination of the recovered airframe and engine was conducted on December 11, 2013. The right wing was separated about 10 inches inboard of the fuel cap; the left wing separated about 25 inches inboard. Both fuel tanks were breached. The fuselage was severely bent and buckled. Flight control continuity was established from the ailerons and from the rudder and elevators to the center fuselage. No portable or airframe oxygen systems were found.
The engine remained partially attached. The vacuum pump, propeller governor, and fuel injection servo were separated. The propeller flange was partially separated; one blade exhibited S-bending and torsional twisting. Internal engine components were free of mechanical damage and showed no heat distress. Both magnetos produced spark. No evidence of any preexisting mechanical malfunction was found.