What happened
On June 27, 2011, a Hughes 500D helicopter, registration C-GLHQ, landed at a remote drilling site near Ambler, Alaska. The landing site consisted of 6-inch by 6-inch wooden beams, which necessitated that the pilot land perpendicular to and directly on the beams using the aircraft's skids.
After the three passengers disembarked, the pilot reduced the engine throttle to flight idle to initiate a mandatory two-minute engine cooldown. The pilot then exited the aircraft to verify that the skids were securely positioned on the supporting timbers. During this time, the helicopter tipped backward, causing the tail rotor to strike the ground. There were no injuries resulting from the incident.
The investigation
Post-accident inspection of the aircraft revealed that the pilot had inadvertently placed the skids behind the aft wooden beam during the landing. This misalignment caused the aircraft to tip backward once the pilot exited the cockpit. The investigation found no mechanical issues with the helicopter prior to the impact. The incident resulted in substantial damage to the tail boom, the tail rotor gearbox, and the tail rotor drive system.