Fact check: False claim planes flying ‘straight and level’ prove the … – USA TODAY

October 31, 2022 flat earth

The claim: Planes flying ‘straight and level’ prove the Earth is flat

One of the first things aspiring pilots learn is straight-and-level flight, a technique that involves maintaining control of a plane while staying at the same altitude and flying in one direction.

A recent Facebook post, though, claims straight-and-level flight supports the long-debunked theory that the Earth is flat.

“Airplanes will fly for hours at the same altitude, never dipping their nose down to follow the curve of the Earth,” says the narrator of a video in the Oct. 6 post.

The same claim appeared in an Instagram post that accumulated more than 3,000 likes before it was deleted.

The narrator describes a hypothetical flight from Portland, Oregon, to Seoul, South Korea, claiming such a trip would require a plane to fly “so far around the Earth that it’s flying downwards, with its nose vertically downwards” and “around the curve of the Earth so that the airplane is now flying upside down.”

“It would have to make that kind of flight path on a globe, which is such an absurdity,” the narrator says.

But this line of thinking is nonsense. Straight-and-level flight doesn’t refer to a literal straight line through the air. Instead, it’s based on keeping a consistent altitude and direction.

The situation described in the video would not result in a plane flying “upside down” because Earth does not have a top or bottom. The force of gravity pulls everything on the planet toward the center, regardless of how the planet is aligned from a viewer’s perspective in space.

USA TODAY reached out to the social media users who shared the post for comment.

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Pilots constantly make adjustments to maintain speed, altitude

Pilots are constantly making adjustments to maintain their speed and altitude, said Greg Feith, a National Association of Flight Instructors board member and former National Transportation Safety Board accident investigator.

“This is the way aircraft maintain a constant pressure altitude and speed,” Feith said. “It is by this mechanism that aircraft follow the curvature of the earth without intervention of the pilots.”

Altitude can be measured using air pressure, giving pilots a consistent measurement regardless of the specific topography at ground level.

“Pressure altitude is very predictable and constant,” Feith said. “The only thing that changes is the aircraft’s height above ground level because the terrain geography changes.”

Flight maps often show planes traveling in an arc, but that’s because Earth is three-dimensional, and maps are two-dimensional. A straight line between two locations on a globe becomes an arc when flattened on a map.

USA TODAY has debunked an array of false claims about the flat Earth theory, including that a compass wouldn’t work if Earth is spherical, that clouds appearing to go behind the sun prove the Earth is flat and that a video showed a NASA astronaut being filmed in front of a green screen.

Lead Stories also debunked the claim.

Our rating: False

Based on our research, we rate FALSE the claim that planes flying “straight and level” prove the Earth is flat. That concept doesn’t mean planes are flying in a literal straight line. It’s a technique that involves flying at a consistent altitude in the same direction. Pilots constantly have to make adjustments to maintain speed and altitude. A plane flying from one location to another would never end up upside down because the Earth does not have an inherent top or bottom.