Casualties unknown

1987-10-27: Mcdonnell Douglas 369D (N47861) — Borrego Springs, CA

Borrego Springs, CA, US

On October 27, 1987, a Mcdonnell Douglas 369D (registration N47861) was involved in an aviation accident near Borrego Springs, CA. Investigators recorded the probable cause as: Engine failure due to oil starvation, which led to insufficient rotor speed during the emergency landing attempt. 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 helicopter suffered a complete engine failure while searching for bighorn sheep over mountains. The pilot attempted an emergency landing but crashed due to insufficient rotor speed, resulting in significant aircraft damage.

What happened

The pilot and three passengers were conducting a low-altitude flight over mountainous terrain with the objective of locating bighorn sheep. Approximately thirty minutes into the sortie, the pilot detected a loud noise accompanied by an unexpected yaw to the left. In response to the developing situation, the pilot maneuvered the aircraft away from the mountains in search of a suitable emergency landing site.

During this phase, the engine lost all power completely. The pilot attempted to extend the glide path to reach the only available landing area. However, because the extended glide was necessary to cover the distance, there was insufficient rotor speed remaining to cushion the impact. The aircraft landed hard, which resulted in the breaking of the right landing skid and caused the helicopter to roll over onto its side.

The investigation

A mechanical examination of the engine revealed that bearing numbers 6 and 7 had failed. The investigation determined that these failures were caused by oil starvation. Despite the examination, the specific reason for the oil starvation could not be determined.

Probable cause

Engine failure due to oil starvation, which led to insufficient rotor speed during the emergency landing attempt.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001213X32371. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.