The aviation safety watchdog has begun gathering cockpit voice and flight data as it launches an investigation the Qantas flight that issued a mayday call after one of its engines failed while it was flying from Auckland to Sydney.
On Wednesday afternoon, QF144 issued a mayday as it was flying over the Tasman Sea, when its left engine failed, forcing pilots to land the Boeing 737 with just one engine.
Flight radar data shows the plane lost altitude and speed during the flight, but the mayday was later downgraded.
The plane landed safely at about 3.30pm, with all 145 passengers disembarking normally and only learning of the engine failure when exiting into an arrivals gate packed with media.
On Wednesday night, the Australian Transport Safety Bureau began its safety investigation into the incident.
Three investigators with experience in aircraft maintenance, aircraft operations, and data recovery had been assigned to the investigation, the ATSB chief commissioner, Angus Mitchell, said on Thursday afternoon.
Mitchell said his agency had requested Qantas quarantine the aircraft’s cockpit voice and flight data recorders.
“Once downloaded, information from those recorders will be analysed at the ATSB’s technical facilities in Canberra,” he said.
Mitchell said other likely investigation activities included interviewing the flight crew, reviewing operator procedures, analysing weather information, examining any relevant engine components, and potentially attending any tear-down inspection of the engine.
“Our investigators will now work methodically to progressively establish the incident’s sequence of events and contextual information, with a view to determining contributing factors and any underlying safety issues, which will be detailed in the investigation’s final report,” Mitchell said.
Mayday calls signal distress to air traffic controllers who prioritise clearing traffic to allow the affected aircraft to land as quickly as possible.
A Qantas spokesperson said that while a mayday was initially issued, it was downgraded to a Pan (possible assistance needed)”.
Qantas said its own engineers were inspecting the plane on Wednesday evening.
“While inflight engine shutdowns are rare, and would naturally be concerning for passengers, our pilots are trained to manage them safely and aircraft are designed to fly for an extended period on one engine.”
Passengers reported hearing the engine “bang” mid-flight. “At the time we didn’t realise it was actually the whole engine had gone,” one woman told the ABC. “We just heard a bang and that was it, so you don’t know.”
Wednesday’s incident was the second time in less than a month that a Qantas flight had an in-air emergency. On 23 December, a Qantas flight from Singapore to London was forced to make an emergency landing in Azerbaijan due to concerns there was smoke in the cargo hold.
Pilots on that flight used squawk code 7700 – the same code issued on the flight from Auckland on Wednesday.
The Australian and International Pilots Association have said it is too early to speculate on the cause of the engine failure.
“This type of incident is extremely rare. We are pleased the expertly trained and professional Qantas pilots took all the right steps to deal with the incident and were able to safely land back in Sydney,” the association said. “The priority of any pilot is the welfare of our passengers and crew.”
The federal transport minister, Catherine King, said she was relieved the plane landed safely.
“Well done to the highly experienced crew for getting the plane safely home,” King tweeted. “Australia’s aviation industry is among the safest in the world because of the dedicated staff working on planes and behind the scenes.”
Emergency crews were on standby at the airport when the plane landed. Fire, police and ambulance personnel were on site as a precautionary measure.
