Aircraft and Operator
The aircraft involved was a Eurocopter Deutschland BK 117 B2C, registration I-HVEN, operated by Elilario SpA. The helicopter was specifically designed for helicopter emergency medical services (HEMS) and civil protection operations, with a maximum capacity of five persons including one or two stretchers.
Flight Details
On 11 June 2004, at approximately 11:45 local time (09:45 UTC), the pilot received an intervention order from the "118" operations center in Bolzano to transport medical personnel to the site of a road accident on provincial road SP 24 at kilometer 5. The helicopter departed from its base in Bressanone at about 11:30 local time. On board were four people: the pilot, a technician, and two medical personnel (a doctor and a paramedic).
Accident Sequence
After arriving at the scene approximately 15 minutes later, the pilot established radio contact with ambulance personnel already present. Following an aerial reconnaissance, the pilot initially decided to land on a dirt area adjacent to the paved road. Two road signs were present at the roadside, one forward and one aft relative to the intended landing spot. As the pilot descended, rotor downwash kicked up dust, prompting him to switch to the paved road SP 24. When the helicopter was about 2 meters above ground, the pilot noticed the injured person was off the roadway and, after a quick consultation with the crew, decided to land on the adjacent parking area to keep the road clear. Since the ground there appeared compact and dust was minimal, he began to translate right to return over the dirt area. To clear a forward road sign, he slightly increased altitude. During this maneuver, while the helicopter was crossing the road edge, the tail rotor struck another road sign at the side of SP 24. The impact shattered the tail rotor blades, causing the helicopter to yaw violently to the right. After two complete rotations, the pilot lowered the collective and set the helicopter down heavily, nearly level. During the first rotation, a main rotor blade struck another nearby sign. The pilot then engaged the rotor brake to stop the main rotor.
Damage and Injuries
No serious consequences were reported for the four occupants or any third parties. The paramedic sustained abdominal bruises described as healable in two days. The helicopter sustained the following damage: destruction of the tail rotor blades, damage to both vertical fins, damage to one main rotor blade, and minor damage to the landing gear. Two road signs on SP 24 at kilometer 5 were also damaged.
Probable Cause
The primary cause of the accident was the pilot's loss of control of the aircraft, caused by damage to the tail rotor after it struck a road sign during the landing phase. Contributing to the event were the failure to identify vertical road signs during the aerial reconnaissance of the chosen landing zone and the pilot's decision, with the helicopter about 2 meters above ground, to abort the landing on the road and translate laterally to an adjacent area without a thorough check for obstacles. The road sign struck by the tail rotor was outside the pilot's field of view.