Primary finding
Probable cause
The gunner’s improper net gun firing, which resulted in a net weight impacting the rotor blades.
Investigator assessment
Analysis narrative
The chief pilot reported that the helicopter pilot told him that, while attempting to net a calf during a caribou capture flight, he got within shooting range for the net gun, but the calf suddenly "broke right." He then turned the helicopter to follow the calf, and while turning, the pilot thought the shot would not be possible and that he should set up for another run, but the gunner fired. The pilot heard a "bang," followed by a strong vibration. The pilot landed the helicopter without further incident. The pilot reported that postaccident examination revealed that one of the main rotor blades had sustained substantial damage, which he assumed was from a net weight. The chief pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.
Source record
Factual narrative
The chief pilot reported that the helicopter pilot reported that, during a caribou capture flight, while attempting to net a calf, he got within shooting range for the net gun but the calf suddenly "broke right" and he turned to follow. While turning, the pilot thought the shot would not be possible and that he should set up for another run, but the gunner fired. The pilot heard a "bang", followed by a strong vibration. The pilot landed the helicopter without further incident. Postaccident, the pilot examined the main rotor blades and observed substantial damage to one of main rotor blades, which he assumed was from a net weight. The chief pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.