The ATSB has released an interim report from its ongoing investigation into an incident where passengers were evacuated from a Saab 340 after flame and smoke were briefly observed from the rear of the aircraft’s left engine during an interrupted engine start.
The aircraft, operated by Regional Express, was being prepared for departure on the morning of 5 April 2022 for a flight from Melbourne to King Island, with two pilots, a flight attendant and 23 passengers on board.
“Drawing upon a preliminary review of CCTV footage, on-board recordings and interviews with the crew, the report details the incident’s sequence of events during the engine start-up sequence,” said ATSB Director Transport Safety Dr Mike Walker.
After the right engine was started, and as the crew began to start the left engine, a ground staff member disconnected the ground power unit from the aircraft prior to receiving the signal from the flight crew to do so, the report details. This interrupted the start-up sequence.
The captain then initiated the interrupted engine start procedure for the left engine, which included motoring (using its starter to rotate the engine with fuel and ignition switched off) to remove any residual fuel from inside the engine.
As the left engine propeller began to rotate, flame and smoke were visible coming from the rear of the left engine for about 3 seconds.
A marshaller, positioned at the front of the aircraft, noticed the flames and began to signal to the flight crew to stop the engine start using the appropriate hand signal. However, the marshaller could not recall the hand signal for fire and instead communicated to the flight crew by mouthing the words ‘smoke’ and ‘flame’ and gesturing to the left engine.
The captain ceased motoring the left engine. At about this time, the flight crew noted that the left engine interstage turbine temperature (ITT) was still rising and in response the captain decided to make a second attempt at motoring. At this time, the marshaller continued to signal to the flight crew that there was a problem.
The report then details the actions of the flight crew, including actioning the engine fire emergency checklist and commanding an evacuation.
Two passengers received minor injuries in the evacuation, which took about 4 minutes.
The report details safety action taken by the operator as a result of the incident, including the development of a new hand signal to indicate an interrupted engine start, and providing ground staff with a training package about dispatch procedures and hand signals.
“This interim report details factual information established in the investigation’s early evidence collection phase, and has been prepared to provide timely information to the industry and public,” said Dr Walker.
“It contains no analysis or findings, which will be detailed in the investigation’s final report.”
The continuing investigation will include a review and examination of flight crew failure management procedures, crew communication and coordination; flight crew, flight attendant and ground staff recurrent training; and on-board recordings.
“Should a critical safety issue be identified during the course of the investigation, the ATSB will immediately notify relevant parties so appropriate and timely safety action can be taken,” Dr Walker noted.