CABRI G2 Helicopter Accident at Hradec Králové

Overview and Flight Details On 10 March 2018, a Hélicopteres Guimbal CABRI G2 helicopter, registration OK-CAB, was involved in an accident at Hradec Králové Airport (LKHK). The aircraft was a light, single-engine, two-seat helicopter with fixed skid landing gear. The accident occurred at 15:05 UTC during a series of training flights intended to complete a type conversion. The pilot and flight instructor were conducting practice landings in autorotation without power recovery. During the second landing, at the moment of ground contact, a main rotor blade severed the tail boom, causing severe damage to the helicopter. No injuries were reported to the crew. ## Crew and Aircraft Information The pilot was a 36-year-old male holding a valid Class 1 medical certificate and a Private Pilot Licence (Helicopters). He had type ratings on Robinson R44 and R22 helicopters and had begun type conversion training on the CABRI G2 on 19 December 2017. The flight instructor was a 34-year-old male holding a Commercial Pilot Licence (Helicopters), a Flight Instructor (Helicopters) qualification, and a type rating on the CABRI G2. The helicopter, manufactured in 2012, had a total time of 1,296 hours and 30 minutes. It was powered by a Lycoming O-360-J2A engine. The aircraft was registered in the Czech Republic and was found to be in a serviceable condition prior to the flight, with no recorded defects in its logbooks. ## Investigation and Findings The accident was investigated by the Institute for Expert Investigation of Causes of Aircraft Accidents (ÚZPLN) in accordance with EU Regulation 996/2010 and ICAO Annex 13. The investigation focused on preventing future accidents without assigning blame or liability. The final report was issued on 18 March 2019. The investigation determined that the damage to the helicopter's structure and powerplant was caused by the contact between the main rotor blades and the tail boom. Following the accident, the helicopter underwent extensive repairs, including the replacement of the tail boom, one main rotor blade, the engine mount, and the Fenestron tail rotor, among other components.