Casualties unknown

2004-05-23: Mooney M20K (N231DL) — Pinedale, WY

Pinedale, WY, US

On May 23, 2004, a Mooney M20K (registration N231DL) was involved in an aviation accident near Pinedale, WY. Investigators recorded the probable cause as: The pilot's inadvertent flight into adverse weather conditions, and his failure to maintain terrain clearance while maneuvering. Contributing factors were the downdraft, the snow shower weather and mountainous terrain. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

A non-instrument rated private pilot descended to cross a mountain pass in central Wyoming, then entered a rapid descent. No mechanical failure was found. The wreckage was located three days later.

Flight and Pilot Information

The pilot, a non-instrument rated private pilot, had been airborne for approximately 3 hours. According to radar data, he descended from 15,500 feet to 14,300 feet to cross the continental divide at Gannett Peak, which has an elevation of 13,804 feet. The descent was attributed to weather conditions.

Descent and Weather Conditions

Radar data indicated that approximately 20 seconds after reaching 14,300 feet, the airplane entered a rate of descent of about 4,200 feet per minute. Satellite imagery and NEXRAD Doppler data, as analyzed by an NTSB meteorologist, suggested that at the pilot's ground track location, the mountain was experiencing light to intermittent snow showers.

Pilot Training and Aircraft Examination

No endorsements were found in the pilot's flight logbook to indicate that he had received any mountain flying training. Search and rescue teams located the airplane three days later. An examination of the wreckage found no evidence of a mechanical failure.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20040528X00684. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.