NTSB Identification: WPR11LA352
14 CFR Part 91: General Aviation
Accident occurred Wednesday, July 27, 2011 in Troutdale, OR
Probable Cause Approval Date: 04/20/2012
Aircraft: EUROCOPTER AS 350 B3, registration: N808LF
Injuries: 4 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The pilot reported that, about 12 minutes into a repositioning flight following a maintenance task performed by a company mechanic, he felt something that he described as similar to a bird strike. The pilot subsequently elected to make a precautionary landing in order to assess the situation. During an examination of the helicopter after the uneventful landing, the pilot discovered that a portion of the tail rotor drive shaft cover was missing and that one main rotor blade and two tail rotor blades had been damaged. Postaccident discussions with the company’s director of maintenance determined that the maintenance staff (who had recently performed a maintenance inspection) and the pilot likely looked at the tail rotor drive shaft cover prior to the accident flight and presumed that it was secure or had been secured by someone else; however, it was not secure and came off during flight. Following the accident, the company implemented a primary mechanic position into its Field Mechanic Procedures in order to mitigate a similar occurrence.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The in-flight separation of the tail rotor drive shaft cover as a result of maintenance personnel not ensuring that it was secured after a maintenance inspection; also causal was the pilot’s inadequate preflight inspection of the helicopter.

Full narrative available

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