Casualties unknown

Engine Failure After Oil Cooler Line Cross-Connection During Restoration Flight (N1451D)

Chino, CA, US

On April 5, 1994, a North American P-51D (registration N1451D) operated by Michael Clarke was involved in an aviation accident near Chino, CA. Investigators recorded the probable cause as: Incorrect installation of oil cooler lines, resulting in a line failure and loss of engine oil, leading to engine failure. 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 2026-06-10Data APIEditorial standards

An aircraft undergoing restoration suffered an engine failure after inadvertently crossed oil cooler lines led to oil loss. The pilot was performing a pre-departure check flight.

Background

The aircraft had been undergoing a major rebuilding and restoration following a previous accident and had not flown for several years. The pilot intended to circle the airport several times to check the aircraft before departing on a cross-country flight to Prescott, Arizona.

Flight Details

Ground witnesses reported that the pilot did not perform the normal preflight ground power checks before departure. The aircraft departed for the planned flight.

Postcrash Examination

Examination after the accident revealed that two oil cooler lines had been inadvertently crossed. One of the oil cooler lines failed as a result of the incorrect installation, causing engine oil to be pumped overboard. Subsequently, the engine sustained a catastrophic internal failure.

Maintenance History

The last logbook entry and documented annual inspection for the airplane were dated 1987. The pilot's last flight physical was dated 1981.

Probable cause

Incorrect installation of oil cooler lines, resulting in a line failure and loss of engine oil, leading to engine failure.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001206X01125. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.