TSB traces 2023 Dash 8-400 engine fire to compressor blade fatigue

Canadian investigators have linked the 2023 inflight failure of a Pratt & Whitney Canada PW150A engine on a De Havilland Canada Dash 8-400 to a fractured low-pressure compressor rotor blade. The Transportation Safety Board of Canada said in a report released on 22 September that the blade failed because of a high-cycle fatigue crack that began below the surface and spread due to mechanical resonance at 26,000rpm.

The aircraft, a WestJet Encore Dash 8-400 registered C-GVEN, was flying from Kamloops to Calgary when the right-side engine surged with a bang after the climb to 25,000ft. The aircraft yawed right and turbine temperature reached 1,100°C, above the 850°C redline. The full-authority digital engine control added fuel in an attempt to recover power, but the TSB said the extra fuel exited through an exhaust duct and caught fire, damaging cowlings, door and fairing components. The crew shut down the engine, declared an emergency and diverted to Kelowna. No passengers or crew were injured.

The report cites 13 similar PW150A low-pressure compressor failures since 2012. The affected rotor has a life limit of 20,000 cycles, but the TSB said this blade failed after 909 cycles.

Working with the manufacturer, the TSB identified possible contributing factors, including temperature and an environmental control system setting that can aggravate the resonance condition.