Casualties unknown

Helicopter Tail Rotor Strike Followed by Drive Shaft Separation and Water Landing (N8395F)

Polk Inlet, AK, US

On June 10, 1992, a Mcdonnell Douglas MD-500D (registration N8395F) operated by Cri Helicopters was involved in an aviation accident near Polk Inlet, AK. Investigators recorded the probable cause as: THE PILOT'S FAILURE TO FOLLOW PROPER PROCEDURE AND THE COMPANY'S INADEQUATE PROCEDURES AND DIRECTIVES. A FACTOR WAS THE UNEVEN 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 2026-06-10Data APIEditorial standards

A helicopter's tail rotor struck muskeg after landing on unstable terrain and premature exit. The pilot found no damage and flew back, but the tail rotor drive shaft separated mid-flight, leading to a water landing.

Incident Details

A helicopter landed on unstable terrain. After touchdown, the pilot and the front seat passenger exited the aircraft while the rear passengers remained inside. The helicopter then rocked backwards, causing the tail rotor to strike the muskeg while the main rotor was still turning slowly.

Post-Strike Actions

The pilot examined the drive train for damage and found none. Believing the aircraft was safe, he decided to fly back to the base of operations. During the return flight, the tail rotor drive shaft separated, resulting in a loss of tail rotor thrust. The pilot subsequently executed a landing in the water.

Company Procedures

According to the pilot and the chief pilot, the company's operations manual and training manual contain no information indicating the appropriate action to take after a blade strike has occurred. The chief pilot further stated that the pilot did not follow the verbal procedure which requires him to remain inside the helicopter until the blades stop rotating.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X14753. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.