Accident Details
On 20 June 2014 at 06:48 UTC, a Robinson R22 BETA II helicopter (registration OK-LPS) departed from Roudnice airport (LKRO) for a business flight to Skuteč airport (LKSK). Approximately 16 minutes after takeoff, while flying near the northwest edge of Hlavenec village, the crew heard a loud bang from the engine compartment. Simultaneously, low rotor RPM audio and visual warnings activated, and both main rotor and engine RPM dropped to 90%.
The pilot immediately reduced collective pitch to enter autorotation and pulled cyclic to increase rotor RPM. Rotor RPM increased slowly, and the helicopter descended in autorotation, avoiding a village and forest. At about 3 meters above the ground, the helicopter experienced a rapid loss of altitude and made a hard landing despite a sharp collective pull. The pilot shut down the engine and called for help. Both occupants remained in their seats due to spinal injuries until rescue services arrived.
Injuries and Damage
Both the pilot and the passenger sustained serious injuries. The helicopter was substantially damaged: the skin on both sides of the fuselage was wrinkled, especially in the lower rear section; the instrument panel displaced and cracked the left side plexiglass; the vertical bulkhead deformed; the tail boom fractured at the fuselage joint; the left fuel tank shifted; and the landing gear skids spread to maximum width, causing contact between the lower fuselage/engine and the ground. The engine mount structure was bent and broken, and the exhaust system deformed.
Aircraft and Engine Information
The helicopter was a Robinson R22 BETA II, serial number 3457, manufactured in 2003. It had a Lycoming O-360-J2A engine. Total airframe hours were 2112 h 30 min. The helicopter was owned and operated by LPS, letecké práce a služby s.r.o., used mainly for training and aerial work. The last 100-hour inspection was on 29 April 2014, after which it flew 82 h 18 min. Fuel tanks (106 L capacity) contained about 80 L of AVGAS 100 LL.
Technical Examination
Post-accident examination focused on the V-belts. The front double V-belt was found split along its entire length and heavily worn, with dry rubber dust inside the belt housing. The rear double V-belt was severely damaged and had fallen out of the helicopter, found on a road in Hlavenec. The belt tensioning mechanism and freewheel clutch functioned correctly. All other damage was consistent with the hard landing.
Pilot Information
The 56-year-old male pilot held a CPL(H) with a valid type rating for the R22 (expiring 31 March 2015) and other ratings. He had 3174 hours on type and 7913 total hours. His last flight before the accident was on 17 June 2014. The passenger, a 63-year-old man, also held a CPL(H) and had experience on the R22.
Meteorological Conditions
The Czech Hydrometeorological Institute reported cold air from the northwest behind a cold front moving southeast. Surface and upper winds were from the northwest.