A passenger on a flight tried for several reasons to open the door of the plane in a completely unexpected incident during the flight, as the plane is at a very high altitude, and the passengers had to intervene and break two bottles of wine on the passenger’s head to subdue and calm him.
But this traveler may not have known that physics is on the side of passengers and cabin crew.
By some calculations within the laws of physics theoretically, a passenger would need 23,600 pounds of force to open an airplane door, the equivalent of two African elephants.
The incident began when the man, identified as Joseph Hoddick of Tampa, Florida, tried to open the exit door about an hour after flying a Delta Boeing 767 from Seattle to Beijing on July 6, according to a statement issued by the FBI. However it seems that the man did not have a complete understanding of physics.
John Paul Clark, professor of aeronautical engineering and director of the Air Transportation Laboratory at the Georgia Institute of Technology, said the pressure inside a typical plane’s cabin never drops below 8,000 feet/2,400 meters above sea level.
The bottom line is that above 8000 feet the pressure inside the cabin becomes higher than the pressure outside, Clark said in an email.
Moreover, aircraft doors are built so that the side closest to the outside is smaller than the side closest to the inside, Clark said. This configuration means that a person cannot lock the plane door from the inside.
And the only way to open it is to pull it in, turn it somehow, and then push it out.
In order to open the plane door at an altitude of more than 8000 feet, you must challenge the pressure difference between the inside and outside of the plane.
But how much is this difference in pressure? Clark offered some estimates. per square inch (75,260 Pa) and the pressure at aircraft altitude or 36,000 feet (11,000 m) is 3.3 pounds per square inch (23,000 Pa).
Clark said the door on the Boeing 767 is closer to 74 inches by 42 inches (1.88 by 1.07 metres).
To calculate the force it would take to pull the door inward at 36,000 feet you need to find the pressure difference and multiply by the area of the door 10.92 psi – 3.3 psi x 74 inches x 42 inches equals about 23,700 psi.
That’s a lot of power, estimated at the weight of roughly 30 grand pianos or roughly six adult male hippopotamuses.
However, the situation changes if the plane is below 8000 feet, Clark said. Below 8000 feet, the pressure is controlled to match the external pressure, so your ear hurts in the last 8000 feet.
Below this altitude there is little or no pressure difference between the inside and outside of the aircraft so it is much easier to pull and open the door as you would on the ground.