efe-epaSydney, Australia

A plane belonging to Australian flag carrier Qantas is set to take off on Friday from New York to Sydney for a test flight lasting nearly 20 hours without layovers – the world's longest – to study the impact of such a lengthy journey on the health of passengers and crew.

The flight, which is scheduled to depart at 9 pm local time (1 am GMT) from the American megalopolis, is the first of three planned test flights involving the new Boeing 757-9s aircraft which are set to cover new direct routes between Sydney and London and New York City.