Qantas Airways may not place an order for planes capable of non-stop London-Sydney flights until early next year, the airline’s chief executive said on Friday after a 19 hour, 19 minute test flight landed in Australia’s biggest city.

Alan Joyce said he saw a “double sunrise” as a passenger aboard the second of three research flights being conducted to help the Australian airline decide on whether to order planes for what would be the world’s longest commercial route.

The intention is to make a decision by the end of the year based on considerations such as aircraft price, seating configuration and a pay agreement with pilots, Joyce said after his return to Sydney.

“An order could follow into early next year,” he told reporters.

Alan Joyce and flight crew had disembarked the Boeing 787-9 Dreamliner as the plane landed at Sydney airport on Friday. Australia’s national carrier Qantas has completed a 19-and-a-half hour non-stop flight from London to Sydney, part of a series of tests to assess the effects of very long-haul flights.

Qantas has named the ultra long-haul project “Project Sunrise” after the airline’s double-sunrise endurance flights during World War Two.

The plane on the London-Sydney research flight, a Boeing 787 Dreamliner, carried 50 passengers and had fuel remaining for roughly another 1 hour 45 minutes of flight time when it landed.

Qantas has been considering an order for either an ultra-long range version of Airbus’ A350-1000 or the Boeing Co 777-8, although the latter plane’s entry into service has been delayed and so Boeing has put together an alternative offer to deal with that.

Captain Helen Trenerry, who led the test flight, said before takeoff on Wednesday that research data including activity monitoring, sleep diaries, cognitive testing and monitoring of melatonin levels would help determine whether the crew mix of one captain, one first officer and two second officers was appropriate or if more experience was needed.

“They will be very, very long flights and fatiguing over the long term,” she said, adding she would like to see regulations in place to limit the trips to around one a month for pilots.

After the flight on Friday she told reporters she would “absolutely” do the flight again but “I don’t know about often”. If Qantas goes ahead, the route would be launched in 2023.

Mark Sedgwick, the president of the Australian and International Pilots Association representing Qantas pilots, said more research would be needed to inform broader fatigue-management plans.

Ultra-long range flights would be a game-changing opportunity for Qantas as it looks to capture a premium from travellers in return for cutting out a stop-over, Citi analysts said in a note to clients published in July.

They forecast non-stop flights from Sydney to London and New York could add A$180 million ($123.4 million) annually to the carrier’s profit before tax, which was A$1.3 billion in the financial year ended June 30.

Qantas is due to hold an investor briefing on Tuesday where it could provide guidance on future capital spending plans.

The airline needs to get pilots to agree on contract terms and a sign-off from Australia’s aviation regulator to launch the flights by 2023.

Qantas on Monday pledged to slash its carbon emissions to net zero by 2050, joining British Airways owner IAG as the industry’s response to climate change activists gathers momentum.

“We’re doing this because it’s the responsible thing to do,” Alan Joyce said in a statement, calling climate change concerns “real”. IAG last month became the first major airline group to make the net zero by 2050 commitment, leading the way amid intense pressure from climate change activists such as Extinction Rebellion and teenager Greta Thunberg.

The high-profile debate has spurred increasing numbers of environmentally conscious travellers and investors, putting pressure on the aviation industry.

The broader industry has committed to halving emissions by 2050 compared to 2005 levels.

Qantas said it was looking to cap net emissions at 2020 levels and will invest A$50 million ($34.3 million) over 10 years to develop sustainable fuel to help lower carbon emissions by 80% compared with traditional jet fuel.

Australia’s national carrier has already experimented by flying a plane from Los Angeles to Melbourne using mustard seed biofuel.

“So we know the technology’s possible,” Joyce told Australian Broadcasting Corporation. “It’s to actually do it commercially and to do it on scale and not impact the other environmental concerns like taking away from food crops or increasing the cost of food crops. That’s why it’ll take some time to get there.”

Reuters