Qantas is taking an even longer nonstop flight, sending passengers from London to Sydney in almost 20 hours

David Slotnick/Business Insider

• Qantas is testing another new contender for the world's longest flight - a nonstop from London to Sydney, part of its "Project Sunrise" initiative.
• The flight, at over 10,000 miles and nearly 20 hours long, follows a test of a slightly shorter nonstop from New York to Sydney that took place in October.
• The airline is using the flight to study how crews and passengers cope with ultra-long-haul travel.
• Business Insider was on board for the first test flight, which landed after 19 hours and 16 minutes.
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The Australian airline Qantas is testing a new nonstop service from London to Sydney, a route that no airline has been able to carry passengers on without stopping for fuel.

The flight, which was scheduled to depart at 6 a.m. GMT on Thursday, follows a successful similar test of a flight from New York to Sydney last month. Business Insider was on board that flight. Qantas has dubbed the test program "Project Sunrise."

The route from London to Sydney is about 500 miles longer than the path from New York, which took the record for the longest-ever passenger flight. However, due to trade winds, the flight is expected to take about the same amount of time.

Qantas flew a Boeing 747-400 from London to Sydney without stopping in 1989. However, that plane did not have any passengers, and was mostly empty to save fuel - it didn't even have a full set of seats.

Airplanes and airlines are more technically advanced than ever before, with better fuel efficiency, longer ranges, and computer-aided logistical planning. But as some flights get longer, the question is whether passengers and flight crews can tolerate more hours in the air without a layover to break things up.

Right now, a commercially viable direct flight between Sydney and New York or London isn't possible. No commercial aircraft has the range to fly the nearly 10,000 miles with a full passenger and cargo load.

Two planes in development from Airbus and Boeing would have that capability. Qantas has said that it will decide by the end of 2019 which one it will use and that it expects to start commercial service as early as 2023.

For the test flight, the airline is using a brand-new Boeing 787-9 Dreamliner. It's took delivery of the jet from Boeing's factory near Seattle, then flew it to London to position for the trial run. To give the plane the range required for the nonstop flight, Qantas will have only about 50 people on board.

Like the New York flight, the London test will serve as a data-gathering mission, with a team of researchers from Sydney University and Monash University monitoring pilots, cabin crew, and passengers' sleep patterns and alertness.

The primary purpose of the flight is to gather empirical data into how the ultra-long flight time affects pilots alertness and rest compared with shorter flights. Currently, Australian aviation regulators prohibit crews to be scheduled for more than 18 hours at a time, even if there are relief crews and rest periods worked in. To make the flights possible, Qantas will have to prove that schedule blocks up to 20 hours are safe.

The airline is also testing a new service flow as part of a jetlag research study, moving passengers to Sydney time immediately following takeoff, and optimizing meals and service around the new time zone.