What happened
A Bell 206B helicopter, operated under charter for the British Columbia Ministry of Forests, was conducting an aerial and surface inspection of logged areas. While attempting to disembark two inspectors at a decommissioned logging road, the pilot attempted an off-level landing by placing only one skid on a gravel mound. During this maneuver, the pilot experienced a sudden vibration and a loud bang.
Upon realizing the site was unstable, the pilot attempted to abort the landing and climb 10 feet. During a subsequent 2-part turn to locate a better site, the pilot noted increasing vibrations and a decay in main rotor speed. The pilot then attempted to land on the sloped road, but the aircraft rolled over upon touchdown, coming to rest nearly upside down. The two passengers sustained injuries, including a head laceration and bruising, while the pilot was uninjured. The aircraft suffered substantial damage.
The investigation
The investigation focused on the mechanical failure and the environmental conditions of the landing site. Investigators found that the main rotor shaft had sheared during the event. While no definitive marks were found on nearby stumps, wood fibers lodged in a blade tip and scratches on the blade surface were consistent with a rotor strike against a stump protruding into the rotor disk area.
It was noted that the passengers had not been briefed for an off-level exit, which differs significantly from a standard landing. Additionally, while shoulder harnesses were available, the passengers were not wearing them at the time of the accident. The aircraft was also operating without an emergency locator transmitter (ELT) because it had been removed for maintenance, though the flight remained within the legal distance limits for such an omission.