The Qantas Boeing 787-9 usually takes 236 passengers and today's journey with a lightened load doubled as a delivery flight and an opportunity for scientists to study the impact of extremely long duration flying.
Qantas is assessing the commercial viability of Project Sunrise which will require new planes, either the yet to fly Boeing 777X or the A350-1000 from rival Airbus. It also needs to make a deal with pilots and will make a call on the ultra-long flights late this year.
It already flies between Perth and London, a distance of 14,500km, but non-stop from eastern cities will allow it to tap into a much bigger market and could appeal to New Zealanders
House of Travel commercial director Brent Thomas said Sydney-London flights could be a "game-changer", especially for South Islanders.
"If you can fly to Sydney and then to London then that's going to be another consideration particularly if you're coming out of the South Island. Instead of having three flights you only have two."
While there are people who "look sideways" at a long, long flight more people were willing to take a flight that was 18 hours or more simply because they just want to get to the destination with fewer hassles.
"If people are able to fly point to point they are willing to pay a little bit more than if they have a stopover on the way through - it makes it so much easier for them," said Thomas.
Airlines can charge a premium for non-stop flights and while they were working hard to innovate, he says for most passengers the flights were something to get through.
For today's flight the menu was turned on its head with supper served at breakfast time to help those on board adjust to different time zones.
Soon after the early morning take-off from London those on board were offered a range of high GI supper options such as chicken broth with macaroni or a steak sandwich, along with a glass of wine and a milk-based panacotta dessert.
Cabin lighting and temperature, stretching and meditation will also play key roles in the research.
During the test flight researchers from the University of Sydney's Charles Perkins Centre as well as the Cooperative Research Centre for Alertness, Safety and Productivity (Alertness CRC) collected passenger and crew data.
Four pilots (on rotation) and six cabin crew will be involved in the data collection, wearing devices to measure activity and light exposure, completing sleep diaries and tests of alertness and reaction time.
Pilots are wearing EEG (electroencephalogram) brain monitoring equipment for the duration of the flight to track brain activity and monitor alertness during their "on" times and quality of sleep during their "rest" periods.
Pilots will also provide researchers with urine samples from before, during and after the flight which will track melatonin levels to establish individual body clock timing.
Cameras are also mounted in the cockpit for the flight duration to record alertness cues and operational activities.
The airline has already run one New York to Sydney test flight and will fly another between the two cities before the end of the year.
Air New Zealand has stolen the march on commercial services to New York from this region, announcing last month it will begin flights late next year on the 14,300km route.
