What happened
On August 30, 2002, an AB 47 G3B helicopter, registration EC-AUD, was performing a local flight at Salerno Pontecagnano airport. After completing an initial flight from Altavilla Silentina and refueling, the pilot began a second short-duration flight with one passenger on board.
During the return to the aerodrome, the pilot initiated a steep approach at an altitude of approximately 800 feet. As the aircraft reached a height of roughly 6 to 7 meters above the ground, the pilot attempted a flare maneuver by simultaneously adjusting the throttle and the collective. During this maneuver, the pilot noted an engine sputter and a sudden drop in RPM. The helicopter subsequently struck the ground with significant force approximately 400 meters from the parking area. While the pilot and passenger escaped the wreckage without injury, the impact and a subsequent fire destroyed the aircraft.
The investigation
The ANSV investigation focused on the flight dynamics during the final approach and the pilot's corrective actions. The investigation examined the aircraft's technical status, noting that the Lycoming TVO 540 B1A engine and the airworthiness certificate were valid at the time of the accident. Meteorological conditions were reported as good, with high visibility and light winds.
Findings
- The pilot executed a steep approach maneuver that likely induced vortex ring state conditions.
- During the flare, the rotor disk entered a turbulent area of airflow.
- In an attempt to counteract the loss of lift, the pilot increased the collective pitch; however, this action increased the circulation within the vortex, further degrading performance.
- The aircraft experienced power settling, where the power required to arrest the descent exceeded the available power, leading to the uncontrolled impact.