Introduction
On 19 December 2005, a serious incident occurred involving an L 410UVP-E aircraft, registration OK-WDC, operated by Silver Air s.r.o. The aircraft was conducting a charter flight (SLD 801) from Prague Ruzyně Airport (LKPR) to Amsterdam (EDDV).
Flight Sequence
The incident took place during the climb phase at flight level 70, shortly after takeoff. The right engine, an M 601E (serial number 913039), suddenly stopped while operating in climb mode with propeller speed 1900 rpm, turbine gas temperature 690°C, and torque 96%. The crew executed the engine shutdown procedure and performed a visual approach to runway 24 at LKPR, landing safely.
Damage and Injuries
No injuries were reported among the crew or passengers. The aircraft itself was not damaged except for the right engine, which sustained heavy damage to its main components. Subsequent disassembly at the manufacturer confirmed severe internal damage.
Investigation Findings
A commission was established by the Czech Institute for the Investigation of Air Accidents (ÚZPLN). The flight data recorder (FDR59B-L) was read out, confirming a sudden engine stoppage without prior exceedance of monitored parameters. The engine was disassembled on 13 January 2006 at the manufacturer's facility. Fractographic analysis of two generator turbine (GT) blades (part numbers T50Y 137 and T50Y 81) revealed fatigue fractures at the blade neck. These failures led to blade liberation from the GT disk, causing consequential damage to other blades during engine operation. No fatigue cracks were found on the remaining GT blades.
Probable Cause
The investigation concluded that the cause of the right engine failure was a fatigue fracture of the neck of two generator turbine blades (part numbers T50Y 137 and T50Y 81). The event was classified as a serious incident due to technical causes.
Additional Considerations
An unrelated event on 16 December 2005, in which a parked aircraft was overturned by a strong wind gust at LKPR, was investigated for possible connection. The commission found no link between that event and the engine failure.
Safety Recommendations
Based on the manufacturer's list of M 601E engines fitted with blades from melt T50Y, the Czech Civil Aviation Authority was to reassess the airworthiness of those engines under its own authority.