Casualties unknown

1989-11-09: Mcdonnell Douglas 369HS (N9213F) — Oklee, MN

Oklee, MN, US

On November 9, 1989, a Mcdonnell Douglas 369HS (registration N9213F) was involved in an aviation accident near Oklee, MN. Investigators recorded the probable cause as: AN UNDETERMINED POWER PLANT FAILURE. FACTORS RELATED TO THE ACCIDENT WERE: THE SNOW COVERED TERRAIN, SNOW, AND GUSTY WIND. 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 experienced a loud bang and engine failure indication while flying low due to snow. During an emergency landing, gusty winds caused both skids to break off. Subsequent engine testing showed no malfunction.

Incident Overview

A pilot reported flying a helicopter at an altitude of 75 to 100 feet above ground level (AGL) due to snowy conditions. During the flight, a loud bang was heard, followed immediately by the illumination of the engine out warning light and the activation of the engine out audio alert. The pilot then maneuvered the helicopter toward a suitable landing area.

Landing and Skid Failure

While approaching the landing area, the helicopter encountered a gust of wind. The right skid contacted the ground and was dug in, causing it to break off. Subsequently, the left skid also broke off. The helicopter came to rest without the skids.

Engine Examination

The engine was removed and sent to the manufacturer's facility for examination and a test run. The test run revealed no issues that would suggest a failure or malfunction of the engine. No anomalies were found that could explain the loud bang or the engine out indications.

Conclusion

The incident involved an unexpected loud bang and engine warning indications, leading to an emergency landing during which both skids detached due to wind conditions. The engine was later determined to be fully functional.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001213X29852. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.