Agustawestland Spa AW109SP N631HC accident near Kamas, Utah

Probable cause

The pilot’s exceedance of the helicopter’s available power while landing in a confined area, which resulted in a loss of tail rotor effectiveness and a hard landing.

NTSB analysis

The pilot of the helicopter reported that he mistakenly added more fuel than was required to complete a mountainous terrain, confined area landing at an elevation of 10,276 ft msl. During his approach to the landing area, the helicopter descended below the tree line preventing a go-around. As the helicopter descended, the pilot increased collective to add power, but he observed a high torque indication of 111% and he felt the “sluggish” performance of the helicopter. The tail rotor effectiveness diminished, an uncommanded right yaw ensued, and the helicopter landed hard, which resulted in substantial damage to the lower fuselage.

The pilot reported that there were no preaccident mechanical failures or malfunctions with the

powered glider that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR25LA006 for the full record.