Qantas' non-stop London to Sydney flight lands after 19 hours

A non-stop flight from London to Sydney successfully landed Down Under 19 hours and 19 minutes after it took off from Heathrow.

The Qantas aircraft, which covered around 11,000 miles (17,800km), completed the journey at 12.28pm Sydney time (1.28am GMT) earlier today.

While it may sound intense, the ultra long-haul cut around two hours off the existing journey, given the midway stop-off.

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With just 50 passengers onboard, the flight was an experiment of sorts.

The "guinea pigs" had their sleep, activity levels and cognitive function monitored to assess for any health risks of being in the air for so long.

If given the okay, Londoners could be flying direct to Sydney in 2023.

The London-Sydney flight follows a similar non-stop journey from New York to the Australian city four weeks ago.

A third and final flight in the experiment, again from New York to Sydney, is due to take off next month.

After today's journey, clips have circulated online of passengers being led in gentle stretches by Qantas staff.

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The airline's CEO plans to redesign the cabins with "move and stretch zones".

"We know travellers want room to move on these direct services and the exercises we encouraged on the first research flight seemed to work really well," CEO Alan Joyce said.

"So, we're definitely looking to incorporate onboard stretching zones and even some simple modifications like overhead handles to encourage low impact exercises."

Deep vein thrombosis

Travelling for more than three hours by any means leaves you at risk of deep vein thrombosis (DVT), according to the NHS.

Not moving for a prolonged period of time causes blood to pool in the lower limbs, which can form a clot.Usually in a deep vein in the leg, clots can block blood flow.

They can then break off and travel to the lungs, triggering a pulmonary embolism.

This prevents oxygenated blood reaching the heart, which pumps it around the body.

A DVT can ultimately damage the lungs, reduce oxygen levels in the blood and even be fatal.

The NHS recommends travellers reduce their risk by walking as often as possible, doing "calf exercises" - raising your heel off the floor and holding for 10 seconds - and drinking plenty of water.

Regular "out of seat movement and activities" were reportedly encouraged on the Qantas flight.

Jet lag

Any long-haul journey leaves a traveller at-risk of jet lag.

This occurs when our normal sleeping pattern is thrown off balance by a new time zone.

Jet lag "cannot be prevented" but its effects can be reduced by drinking lots of water and sleeping at the normal time for the destination, according to the NHS.

The Qantas flight reportedly had a specific "lighting schedule" that "maximised adaptation to the destination time zone".

It took off at 6am London time, with passengers almost immediately being served an evening meal.

"Eating supper at breakfast time [aims to encourage the passengers] to sleep at 10am in the morning London time to help avoid light and reset their body clock to Sydney time," Professor Corinne Caillaud from the Charles Perkins Centre in Sydney - which "designed" the flight with Qantas - said.

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After take-off, passengers were given a "high GI" dinner of chicken broth with macaroni or a steak sandwich.

This contradicts NHS advice, which urges travellers to avoid large meals.

The passengers were also offered a glass of wine, despite the health service warning "too much alcohol can make jet lag worse".

And while a glass of wine may help you nod off, it also raises the risk of DVT.

However, keeping active with the flight's gentle "work out" could help combat jet lag.

While a new time zone may leave you exhausted, jet lag is not serious, with most adapting to their new routine within a few days, according to the NHS.

Colds

As if jet lag and DVT were not enough to worry about, flying could leave you battling a cold.

Modern planes have reportedly been designed to recirculate air to maximise fuel efficiency.

While many travellers blame this for their inevitable sniffles, studies are increasingly showing recirculated air is no worse than that which is "fresh".

Scientists from the University of California, San Francisco, found 19% of those flying in recirculated cabin air developed "post-flight respiratory symptoms".

This is compared to 21% on aeroplanes with fresh air.

The rate of runny noses and colds were also similar at 10% and 11%, respectively.

Instead, reduced outdoor air ventilation is now thought to be responsible for the "higher than normal viral load", according to scientists from the University of Victoria in Canada.

"Overlapping personal airspaces" and "direct person-to-person contact" may also play a role in infection transmission.

And being in the air too long could also affect our so-called "mucociliary clearance system".

This describes the thin layer of mucus that keeps the tiny hairs in our nose moving.

The hairs, called cilia, work to trap pathogens. These then get moved from the nose and throat to the stomach, where they are destroyed.

Dry air, linked to low humidity, can leave mucus too thick to be moved.

For flights over an hour, humidity is usually below 10%. This falls to less than 5% on longer trips, the Canadian scientists wrote.

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The ultra long-haul Qantas flight could therefore leave travellers particularly at-risk of the sniffles.

The airline has not released details on whether it plans to combat the transmission of colds and other infections.

In addition to all the above, pictures have surfaced online of the flight's passengers wearing "device technology" that "tracks their movement and light exposure".

This is thought to be part of the trial and is not expected to be offered to travellers as standard.

The pilots also wore "brain monitoring equipment" to test their reaction times and the quality of their rest.

Qantas already flies non-stop for 17 hours between London and Perth.

"The final frontier is New York and London to the east coast of Australia non-stop and we are hopeful of conquering that by 2023 if we can make all elements of the business case stack up," Mr Joyce said.

"I've had business travellers tell me they'd rather stay on board and watch an extra episode of their favourite show before arriving at their final destination, rather than spending 90 minutes on the ground waiting for a connecting flight.

"I've also had a few parents tell me they would rather not disturb their kids if they are settled in and avoid having to bundle them and all their carry-on luggage off and back on a flight during a stopover.

"So, there is definitely support for the non-stop flights".

One such supporter is Yahoo News UK's assistant editor Matilda Long, who flew non-stop from London to Perth last year.

"Not having to wake up when you've finally dozed off to trudge through security was a welcome relief", she said.

"Given the chance, I'd choose the ultra long-haul again next time."

- This article originally appeared on Yahoo UK