KATHMANDU: An investigation into the crash of a Simrik Air helicopter in Sankhuwasabha on 5 May 2023 has concluded that pilot overcorrection during a partial hover manoeuvre caused the fatal accident.

The final report states that the AS350 B3e helicopter (9N-AJZ) was engaged in a routine chartered cargo sling operation for the Upper Arun hydropower construction project when the accident occurred in the Siprung area. It was the helicopter's 17th flight of the day, the second-to-last one scheduled. 

During a left skid contact partial hover, attempted because a full touchdown landing site was unavailable,  the Pilot-in-Command applied excessive left cyclic control input, causing the main rotor to strike a nearby drilling machine.

The helicopter subsequently lost control. The tail rotor struck the ground and detached, and the aircraft toppled downslope before coming to rest. Of the five persons on board, one flight crew member, two sling crew and two passengers, one passenger, identified as a local helper, died. The pilot sustained serious injuries, while another passenger suffered minor injuries. The aircraft was substantially damaged. The report notes that the helicopter had undergone a 600-hour inspection on 2 May 2023 and was maintained in accordance with approved requirements.

The investigation further found that the local helper involved had not been trained or briefed on partial hover operations. At the time of the accident, no Standard Operating Procedures (SOPs) or specific pilot training frameworks for skid contact partial hover manoeuvres existed in Nepal. 

The report recommends that operators develop partial hover SOPs for approval by the Civil Aviation Authority of Nepal (CAAN), ensure only trained personnel are onboard during sling operations, and that CAAN introduce dedicated training syllabi for such specialised manoeuvres.

Since the accident, key safety protocols have been introduced. The Civil Aviation Authority of Nepal (CAAN) mandated simulator training for all helicopter pilots as of January 1, 2024. Additionally, Simrik Air has developed and sought approval for a new SOP on partial hovering operations.