Introduction
On 15 October 2011, at 08:27 UTC, a motorized glider L-13SW Vivat, registration OK-6114, experienced an engine failure during flight near the village of Lískovice. The aircraft was owned by Aeroklub České republiky and operated by Aeroklub Hořice v Podkrkonoší. The pilot was the sole occupant.
Incident Details
Approximately five minutes after takeoff from runway 30 of Hořice airfield (LKHC), after climbing to about 300 meters AGL, the pilot heard a bang from the forward part of the aircraft followed by engine failure. The pilot transitioned to gliding flight and performed a forced landing on a former agricultural area south of Lískovice. The aircraft landed with the landing gear extended; the engine was not operating at touchdown. The pilot exited the aircraft and reported the incident to Hořice airfield.
Investigation Findings
The aircraft, a motorized glider designed for recreational and navigational flying, had a valid airworthiness certificate and was in service since 1986. The engine was a Mikron III S, serial number 36087, with a total of 2,068 hours and 25 minutes since new, and 292 hours and 39 minutes since its last overhaul. The fuel used was automotive gasoline Ba 95, with 20 liters on board and 8 liters of oil.
Post-incident technical inspection revealed a breach in the engine casing. Further examination showed a fractured connecting rod and a broken piston in the second cylinder, along with damage to the camshaft. The interior of the engine was covered in oil film, with fragments of the connecting rod found in the casing. Review of maintenance records indicated that the defective connecting rod had not been subject to radiographic inspection, as it was part of an 'S' series engine that did not require such checks.
The forced landing site was a grassy former agricultural area without obstacles, known to the pilot. No injuries to the pilot and no damage to the aircraft were reported. The event was classified as a serious incident due to the extent of engine damage.
Conclusion
The cause of the serious incident was engine failure resulting from a connecting rod failure. The connecting rod had developed a hidden defect during operation. No safety recommendations were issued by the investigation authority.