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The flight crew of a Dash 8 turboprop airliner elected to return to Perth Airport soon after take-off after detecting a popping or banging sound from the vicinity of the left engine, an ATSB investigation report details.
The Skippers Aviation DHC-8-315 (Dash 8-300) had departed Perth Airport for the Duketon Gold Mine on 23 April 2019. Climbing through approximately 250 feet above ground level, as the landing gear was being retracted, the flight crew heard a popping or banging sound from the vicinity of the number one (left) engine and detected a reduction in power from that engine. At about the same time, the pilot flying experienced a yaw through the aircraft controls. The crew also noted a gradual reduction in right engine power.
The flight crew decided not to shut down the malfunctioning engine immediately, allowing them to concentrate on continuing the climb during a period of increased workload. Both engines responded to an increase in power, however the crew elected to return to Perth Airport, where an uneventful landing was conducted.
A subsequent inspection of both engines found erosion damage to both high pressure turbines, with the damage to the left engine more pronounced. This erosion damage likely disrupted the airflow through the left engine, inducing the symptoms reported by the crew.
The ATSB investigation report stresses that a partial power loss presents a more complex scenario to flight crew than a complete engine failure. In these circumstances the engine is still providing some power but the power may be unreliable, and that reliability may be difficult to assess.
In this case, while the affected engine appeared to return to normal operation, the flight crew remained committed to returning to the airport. Abnormal engine operation, even if only transient, can be an indication of a developing fault and therefore the safest course of action is to discontinue the flight as soon as possible.
The investigation’s safety messages note that this occurrence highlights the benefits of timely and appropriate flight crew action in response to a power loss on take-off.
Read the report: Engine malfunction and return involving Bombardier DHC-8-315, VH-XKJ, Perth Airport, Western Australia, on 23 April 2019