Eurocopter AS350 N160SH accident near Ninilchik, Alaska

Probable cause

A loss of engine power for an undetermined reason.

NTSB analysis

The pilot reported that he was transporting workers to and from various mining sites about 3 miles from the main camp. The pilot flew to a high mountainside helipad, which was located about 2,750 ft mean-sea-level (msl) cut into a rocky steep slope and disembarked 2 passengers. He flew the helicopter to a nearby site and waited a short time for the off going workers to be ready for pick up. He departed and made another approach to the helipad. The pilot stated that when the helicopter was about 25 ft from the landing site, at very slow forward airspeed, the engine "flamed out" and the helicopter yawed right. The pilot continued the right turn, lowered the collective and attempted to autorotate to a level area about 600 ft below the helipad. When the pilot realized that the helicopter could not make the intended site, he slowed down by applying some aft cyclic and increasing collective to cushion the touchdown. The helicopter landed on the skids facing down the mountain and continued to slide. The left skid impacted a rock and the helicopter rolled over and continued down the mountain, resulting in the tail boom separating. The helicopter came to rest on a drill pad under construction about 200 ft below the helipad. The tail section, fuselage and main rotor blades sustained substantial damage. The examination of the airframe did not reveal any discrepancies. The engine was placed on an engine test cell and two tests were run for a total of 2 hours 23 minutes with 9 starts. The engine demonstrated normal operation during testing. No abnormal engine operation, uncommanded shutdown, or loss of power control was observed.

Text from the NTSB. Open the NTSB docket for ANC20LA083 for the full record.