What happened
On July 20, 2016, an Airbus Helicopters AS 350 B3, registration LN-OSN, was engaged in a power line construction project in Lavangen, Norway. The mission involved transporting personnel and materials as part of a larger utility project. During a stop at Base 40, a change in the mission plan occurred when instructions were received to pick up personnel from a different location.
While the pilot was performing a secondary transport leg, a ground crew member attached a longline equipped with a 700 kg weight to the aircraft's cargo hook. The pilot, unaware of this attachment, departed the base. Approximately four seconds after takeoff, the aircraft experienced violent jerking motions and the nose pitched downward. The attached weight dragged along the terrain, snagging on uneven ground and trees. The impact caused damage to the landing gear and the main rotor blades, though there were no fatalities or injuries to the single occupant.
The investigation
The Norwegian Safety Investigation Authority (NSIA) examined the communication protocols and operational procedures used during the mission. The investigation focused on how the weight was attached without the pilot's awareness and why the change in mission parameters was not effectively communicated. Investigators reviewed the radio equipment used by the ground crew and the pilot, as well as the risk assessment documentation used for the day's tasks.
Findings
- Communication failure: A lack of clear communication between the ground crew and the pilot regarding the change in mission plans led to a misunder lack of mutual understanding. The ground crew member attached the longline without confirming the pilot's awareness.
- Inadequate radio equipment: The ground crew's radio was not suitable for use in high-noise environments, such as near an active helicopter engine, as it lacked noise-canceling headsets.
- Incomplete risk assessment: The 'Safe Job Analysis' performed for the day's tasks did not sufficiently account for the risks introduced by unforeseen changes to the original plan.
- Lack of visual verification: The pilot did not utilize the onboard cargo mirror to verify that the underside of the aircraft was clear before departure.
- Perception of risk: A general perception that passenger transport operations carried low risk may have contributed to the pilot's decision to depart based only on a signal from passengers rather than a full check of the aircraft's status.