Helicopter Incident in Nowa Wieś Wrocławska (SP-HXT)

Incident Overview On 10 February 2020, the crew of the Wrocław branch of the Air Rescue Service (LPR) was dispatched to a road accident on the A4 motorway near Nowa Wieś Wrocławska. The helicopter, an EC 135-P2+ with registration SP-HXT, took off and proceeded to the scene without incident. ## Event Description After selecting a landing site, the crew initiated a landing approach into the wind. During the vertical descent at approximately 30 feet and 20 knots, the helicopter experienced a sudden loss of airspeed. It initially rotated about 45 degrees to the right while drifting laterally. The pilot briefly stabilized the aircraft, but it then began rotating around its vertical axis to the right, completing approximately 1.5 turns while gaining altitude. To avoid a collision with the ground or terrain obstacles, the pilot entered a recovery maneuver by increasing the main rotor collective pitch to 70 percent. This action caused the torque limits of both engine shafts to be exceeded. The crew decided to abort the mission and return to the HEMS base at EPWR. The return flight and landing were uneventful. ## Post-Incident Actions After shutting down the powerplant, the pilot reported the incident to the on-duty engineer at the Technical Coordination Center. The helicopter was grounded due to the torque exceedances, which were classified as Category F. The left engine shaft exceeded its limit by 96.5% for 2.875 seconds, and the right engine shaft by 95.8% for 2.750 seconds. A maintenance review was conducted under CRS 106/014/HXT/1/1 in the recommended Category F following the torque exceedances. No irregularities were found, and the helicopter was returned to service. ## Cause and Recommendations The investigation determined that the incident was caused by the helicopter entering a strong stream of disturbed air and its interaction with terrain obstacles, resulting in a loss of tail rotor effectiveness (LTE). The commission accepted the following preventive recommendations: - Brief the operational personnel of the Air Rescue Service on the incident. - During the next periodic training for flight personnel, discuss the conditions that lead to loss of tail rotor effectiveness (TLE) and methods for preventing it. No additional safety recommendations were formulated.