Casualties unknown

1996-08-25: Mooney M20J (N4538H) — Lubbock, TX

Lubbock, TX, US

On August 25, 1996, a Mooney M20J (registration N4538H) was involved in an aviation accident near Lubbock, TX. Investigators recorded the probable cause as: Loosening of both magneto retention nuts, resulting in magneto disengagement and subsequent engine power loss. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 8 related events involving the same aircraft type or operator are linked below.

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

While climbing on an IFR flight in VMC, the pilot declared an emergency due to engine power loss. The airplane landed short of Reese AFB in a cotton field, sustaining damage. Postaccident examination revealed loosened magneto retention nuts.

Incident

During a climb to cruise altitude, between 5,000 and 6,000 feet mean sea level, while operating under instrument flight rules in visual meteorological conditions, the pilot declared an emergency. The pilot reported that the engine was cutting out and that manifold pressure and RPM were low. The pilot attempted to reach Reese Air Force Base, located approximately 3 to 4 miles away, but the airplane landed short of the airport in a cotton field.

During the landing roll, the right main landing gear collapsed, and the right wing separated from the airframe at the forward attachment point.

Investigation

A postaccident examination conducted by an inspector from the Federal Aviation Administration (FAA) found that both retention nuts securing the single-drive magneto to the engine had loosened. Consequently, the magneto became disengaged from its drive gear. The inspector noted that the magneto had been installed with the correct hardware.

Maintenance records indicated that the magneto had been overhauled and reinstalled during an engine overhaul on April 12, 1996. The airplane had accumulated 120 flight hours since that installation.

Probable cause

Loosening of both magneto retention nuts, resulting in magneto disengagement and subsequent engine power loss.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001208X06509. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.