Cessna 150F N8735G

The airplane collided with mountainous terrain at 2,400 feet mean sea level following an entry into a spiral descent from 7,300 feet. After takeoff from the departure airport, the 77-year old pilot contacted Los Angeles Air Route Traffic Control Center (ARTCC) at 1019 and wanted VFR advisories to his destination. When radar contact was established, the controller noted that the airplane was nearly in an active restricted area. The controller assisted the pilot to navigate around the restricted area as the flight climbed to a mode C reported altitude of 6,500 feet. A short time later, the pilot asked the controller to help him find the destination airport and the controller gave the pilot a suggested heading to fly. At 1037, the pilot ceased talking on the radio and attempts by the controller to reestablish contact by using other airborne airplanes to relay messages was unsuccessful. The controller reported that the airplane then began a left descending spiral turn. Recorded radar data revealed that the airplane climbed at an average rate of 500 feet per minute until 6,500 feet, which was achieved at 1039:41. After that time, the airplane continued to climb with rates that varied from zero to 500 feet per minute. At 1045:28, the airplane reached 7,300 feet, then began a descent for 1 minute down to 7,100 feet, then a climb back to 7,300. At 1047:04, the mode C altitude reports showed a descent at an average rate of just over 1,000 feet per minute in a left descending spiral turn with about a 2,000-foot diameter, which continued in excess of 900 degrees (at least 2 1/2 complete turns). The rate of descent computed from the mode C altitude reports began about 500 feet per minute and increased to about 1,500 feet per minute by the time of the last two secondary beacon returns. The last secondary beacon return showed a mode C reported altitude of 4,100 feet and was located about 0.6 nautical miles east of the impact location. Ground based witnesses at a small airstrip about 10 miles southeast of the accident location reported that they saw the airplane fly overhead and a short time later saw the smoke rising from the accident site. The winds were described as calm and the skies clear. Although the wreckage was thermally destroyed in a post impact fire, no preimpact mechaninal malfunctions or failures were noted in the remaining elements. Toxicological tests were negative for carbon monoxide, alcohol, and drugs. The autopsy found left ventricular hypertophy and microscopic myocardial fibrosis evident in the heart, with other findings consistent with hypertension. The attesting pathologist reported that while it is possible that a sudden cardiac event or hypertensive intracerebral event could have contributed to the accident sequence, such findings could not be determined by the autopsy.

Quoted verbatim from the NTSB record.