The world’s longest commercial flights, by the numbers

Last week, Singapore Airlines launched what is the longest regularly scheduled flight in the world—at least for the moment.

The ultra-long-haul trip is a nonstop connection between New York’s John F. Kennedy International Airport and Singapore’s Changi Airport. It employs an Airbus A350-900 aircraft to carry passengers and cargo between those two very distant locations.

We spoke with the captain who piloted the plane on the flight’s inaugural leg: It was a trip that departed eastward from Singapore to New York City on Monday, November 9. Here’s how the flight’s very impressive metrics break down.

16 hours and 58 minutes in the air

The aircraft that journeyed from Asia to North America was aloft for nearly 17 hours, according to Captain Gopala Subramaniam, the airline’s deputy chief pilot for its A350 fleet; he spoke with PopSci from Singapore earlier this week. But actual flight time is different from a metric known as the “block time,” which represents a longer, gate-to-gate period that includes moments like taxiing to and from the runway.

In this case, the block time for the flights going from Singapore to New York (flight number SQ24) is officially 18 hours and 5 minutes. The block time is even longer for the flight that goes the other direction: from New York to Singapore, which is SQ23. That’s because prevailing winds work against the aircraft’s favor in that direction. The block time in that case is 18 hours and 40 minutes, making that specific flight the world’s longest right now. Recently, a flight that left New York for Singapore on November 11, and landed on November 13, had a flight time of 17 hours and 31 minutes.

This New York to Singapore route may be the longest in the world at the moment, but there was a slightly longer one previously, measured by block time: The airline’s Newark, New Jersey route to Singapore. That one had a block time of 18 hours and 45 minutes. “It’s been suspended because of COVID-19, but we have every intention of relaunching that flight when market conditions allow,” notes James Boyd, a vice president for public relations at the airline. So that flight, although not currently operating, has a longer block than the Kennedy one by a whopping five minutes.

These flights between the New York area and Singapore are not the longest flights to have ever occurred, however. For example, last year, Qantas famously tested out three globe-spanning journeys it referred to as “research” flights for “Project Sunrise.” Each of the three jaunts to Sydney (one from New York in October; one from London in November; and a third from New York again in December) lasted more than 19 hours. But the coronavirus pandemic has understandably scrambled, or at least delayed, Qantas’s sunny plans.

8,984 nautical miles

The aircraft’s route on the flight from Singapore to JFK covered nearly 9,000 nautical miles, which translates to over 10,000 standard miles—that’s roughly four times the distance from New York to Los Angeles. Here’s the route they took from Singapore: “For that particular flight, we went north of the Philippines, south of Taiwan, [and] south of Japan,” he recalls. “We set our path towards Anchorage; we flew north of Edmonton [Canada]; then we came down, we flew north of Chicago before coming into JFK.” Easy.

About 238,540 pounds of fuel

That was the quantity of fuel that the aircraft had on board for Subramaniam’s flight from Singapore to New York last week. Pilots measure fuel by weight, not volume, since the volume can change in response to temperature. Singapore Airlines measures their fuel capacity using the metric system, so the plane under Subramaniam’s command had 108.2 tonnes of fuel on board.

Of course, the plane burns through the fuel as it travels. A long-haul aircraft like this is much heavier when it takes off than when it lands—that’s the reason a pilot may decide to dump fuel if they need to return to the airport they took off from right away in an emergency.

On this flight, Subramaniam says the aircraft consumed nearly 97,500 kilograms of fuel, which is around 214,951 pounds—the weight of more than 70 Toyota Corollas in fuel. It still had approximately 23,598 pounds of fuel left when it touched down.

85% the speed of sound

The aircraft’s cruise speed was Mach 0.85, or 85% the speed of sound. “This is quite fast, actually, on an Airbus aircraft,” Subramaniam says. He notes that an Airbus A330 travels at Mach 0.82 mach, for example; the A330 is another wide-body, twin-engine aircraft. A Boeing 777, he adds, travels at about Mach 0.84. (Like the A350, a Boeing 787 Dreamliner also flies at Mach 0.85.)

4 pilots

Of course, Subramaniam didn’t fly the aircraft for the entire 17 hours. The flight carried two flight crews: two captains, and two first officers. The second team was the “relief” set of pilots. Subramaniam piloted the aircraft for the first 3.5 hours or so, and then rested once the relief captain took over for another 3.5 hours. He says he actually got some dozing done once it was his break time. Near Taiwan, “I was quite tired, and I was ready to go to sleep,” he recalls. From there, he worked for another 4.5 hours, then took another 4.5 hour break, then piloted the plane for the landing.

When he’s sitting in the captain’s seat, Subramaniam notes that he does calf raises to mitigate the risks of deep-vein thrombosis. “Just to get the blood circulation going,” he says. A calf raise involves lifting your heels off the ground, and isn’t a bad thing for a passenger to do on a long flight, either.

And a green glow…

A phenomenon caught his eye when they were up north. “After we passed Anchorage, we saw something from a distance that looked like the Northern Lights, but we weren’t able to confirm it,” he recalls. “It looked a little bit greenish in the atmosphere.”

“It just fascinated me and the rest of the crew,” he adds.