Bombardier said the sudden loss of power and uncontained failure of a Pratt & Whitney PW1500G Geared Turbofan (GTF) engine on the Bombardier CSeries test aircraft has been traced to the low pressure turbine (LPT).
The incident which took place during ground runs in Mirabel, Quebec on May 29, damaged the aircraft and resulted in grounding of CSeries flight test fleet.
The low pressure turbine powers the fan and low pressure compressor, extracting energy from the hot gases produced by the engine’s combustion chamber and high pressure turbine.
German MTU is responsible for the high-speed low-pressure turbine. In the turbine, the energy of the gases exiting the combustion chamber at high pressures and velocities is converted into rotational energy, hence the turbine must be capable of withstanding much higher stresses than the compressor, i.e. high gas temperatures and extreme centrifugal forces of several tons acting on the disk rims.
Bombardier said, the failed engine was earlier known to have problems and was repaired from its facility.
It also added the engine failure was due to a manufacturing defect, rather than a design flaw and not caused by the unique gear system.
The engine uses an advanced planetary gear system which decouples the fan from the low-pressure turbine so that either component runs at its optimum speed for improved efficiency.