Primary finding
Probable cause
The pilot failed to maintain tail rotor clearance from obstacles during landing.
Investigator assessment
Analysis narrative
The helicopter's tail rotor struck a rock outcropping during a confined landing at a remote mountain site. The pilot was moving two surveyors up the side of the southern slope of a mountain canyon. He dropped the surveyors off at a small saddle on a ridge, and departed to locate the next site upslope. He found a rocky outcropping that he thought would be a good landing site, and made one approach, but did not like the location due to uneven terrain. He then hovered over to another site a few yards away and proceeded to land. During the landing the tail rotor made contact with a small rock outcropping. Feeling the contact he proceeded to execute a successful autorotative landing from a hover.
Source record
Factual narrative
On September 21, 2005, about 1007 Pacific daylight time, a Bell 407, N702WP, tail rotor struck a rock outcropping during a confined area landing 8.6 miles northwest of the Inyokern Airport, Inyokern, California. Los Angeles City Department of Water and Power operated the helicopter under the provisions of 14 CFR Part 91. The airline transport pilot was not injured and the helicopter was substantially damaged. Visual meteorological conditions prevailed, and a company flight plan was in effect. The public-use flight originated at Hokinson Heliport, Sylmar, California, at 0630. The pilot stated in the Pilot/Operator Aircraft Accident Report (NTSB Form 6120 1/2) that he was moving two surveyors up the side of the southern slope of a mountain canyon. He dropped the surveyors off at a small saddle on a ridge and departed to locate the next site upslope. He found a rocky outcropping that he thought would be a good landing site, and made one approach, but did not like the location due to uneven terrain. He then hovered over to another site a few yards away and proceeded to land. During the landing the tail rotor made contact with a small rock outcropping. Feeling the contact he proceeded to execute a successful autorotative landing from a hover.