Accident Overview
A Bell 206B helicopter went out of control and crashed while landing at a helipad located at an elevation of 5,720 feet. The aircraft collided with terrain and came to rest on its left side.
Pilot Report
The pilot reported that he terminated the approach at a hover approximately 8 to 10 feet above the ground. He then began to spin to the right, despite applying full left pedal input. After one and a half to two turns, the pilot attempted to recover by lowering the nose and reducing power. The helicopter continued to spin and subsequently collided with the terrain.
Environmental Conditions
The approximate density altitude for the helipad was 6,800 feet mean sea level. Advisory Circular 61-13B states that when the destination is at a higher altitude and/or higher temperature and moisture content prevail, sufficient power may not be available to hover at the destination with the existing gross weight. The manual also recommends that a normal approach to the surface should be used when high density altitude or heavily loaded conditions exist.
Regulatory Definition
The Federal Aviation Administration defines 'unanticipated right yaw' as an occurrence of an uncommanded right yaw rate which does not subside on its own and which, if not corrected, can result in loss of aircraft control.