What happened
On August 17, 2005, at approximately 15:17 local time, a Eurocopter BK 117 C1, registration D-HDSR, was conducting a Helicopter Emergency Medical Service (HEMS) mission near Gombio, Italy. The aircraft had departed from Parma to provide medical assistance.
While performing a reconnaissance of the landing site, the pilot was hovering at an altitude of approximately 1 to 2 meters above the ground. During this phase, the pilot observed an approaching ambulance that was positioned too close to the rotor system. To maintain safety, the pilot attempted to back the aircraft away from the vehicle. During this retreating maneuver, the tail rotor struck the branches of a tree, causing a violent yaw to the right. The pilot experienced a loss of pedal effectiveness and performed an immediate landing, which resulted in a 180-degree clockwise rotation around the yaw axis. Following the impact, the pilot promptly shut down the engines, disconnected the fuel pumps, and deactivated the battery.
All four occupants (the pilot, co-pilot, and two passengers) escaped the incident uninjured.
The investigation
The ANSV investigation focused on the mechanical state of the aircraft and the sequence of the maneuver. Examination of the wreckage revealed significant damage, including broken tail rotor blades, a deformed landing gear, and a ruptured vertical stabilizer. Notably, the impact caused the failure of the Thomas joint between the tail gearbox input pinion and the drive shaft, as well as damage to the tail rotor pitch control bracket and servo actuator rod.
Investigators found that the landing gear's deformation actually helped dissipate kinetic energy, protecting the fuselage structure from significant damage. The investigation confirmed that the aircraft was in a fully airworthy condition prior to the event, and no technical failures were identified as the cause of the incident.