What happened
On November 23, 2024, an Airbus BK117 C-2 (registration F-HSOC) operated by Babcock MCS France was performing an air ambulance mission near Montanel. The crew was responding to a road accident involving two victims in serious condition. After a reconnaissance flight, the pilot selected a paved road adjacent to a cemetery car park for landing, opting against two nearby fields due to ground conditions.
As the helicopter approached a hover approximately two feet above the ground, the pilot attempted a left-hand yaw rotation to align the aircraft with the road's slope and facilitate stretcher loading. During this maneuver, the tail rotor struck an unidentified object or obstacle, causing a sudden loss of yaw control and a subsequent right-hand rotation. The pilot immediately lowered the collective pitch to touch down and stop the rotation. The impact resulted in the destruction of both tail rotor blades and damage to the tail rotor drive shaft.
The investigation
The BEA examined the flight data recorder (CVFDR), aircraft damage, and crew statements. Investigators analyzed the site layout, noting the presence of a stone wall, a hedge, and a bank. While no fixed structures showed damage consistent with a high-speed strike, the investigation focused on the tail rotor's interaction with the environment during the rotation. The investigation also reviewed the operator's manual regarding landing area selection and the psychological factors affecting the crew.
Findings
Several factors contributed to the accident:
- Operational pressure: The pilot experienced time pressure related to the critical condition of the accident victims and pressure to accommodate the medical personnel's need for easy stretcher loading.
- Insufficient communication: There was a lack of verbalized safety checks between the pilot and the technical crew member during the yaw maneuver. The crew was primarily focused on the bank to their left, neglecting to monitor the area to the right.
- Inadequate obstacle assessment: While the crew identified some hazards, they did not adequately consider the proximity of the barrier and the potential for objects to be displaced by rotor downwash during the rotation.
Safety action
Following the accident, the operator issued a "Safety Flash" to its crews, emphasizing the need for systematic action planning, clear communication of intentions (using the NITS format), and the prioritization of aircraft safety over the convenience of medical maneuvers. The operator also updated its Operations Manual to provide more detailed guidance on managing obstacles and maneuvering in ground effect.