How are Aircraft Doors Sealed?
When ascending into higher elevations, air pressure gradually lessens and breathing can become more labored. At high enough altitudes, conditions of oxygen, pressure, and temperature can even become dangerous to humans. Due to this, aircraft have been specifically engineered to maintain a comfortably pressured environment for passengers during flight. This means that every component must be designed to withstand the difference of pressure on the inside and outside of the fuselage. While windows and structures remain permanently closed and/or sealed, the main doors are openable. Luckily for any worried passenger, their design specifically prevents any possible openings or malfunction during flight.
Despite the possible worry that a frenzied passenger may attempt to open a door mid-flight, actually prying it open is near impossible by oneself, even if left to their own devices. This is due to both natural and mechanical forces that keep the door shut. Aircraft doors
are considered “self-sealing” because despite also having mechanical locks, they really only need pressure to stay shut. Like a cork in a bottle, the aircraft door is shaped like a wedge and can only be opened inwards into the cabin. With the pressure of the cabin being much greater than that of the outside during flight, there can be upwards of 20,000 pounds of force that hold a door shut while at peak altitudes, Even at low altitudes of 2,000 feet, there is still around 4,000 pounds of pressure that even heavy bodybuilders could not overcome.
Beyond the natural pressure sealing solution, there are also mechanical cabin door seal parts
that ensure the aircraft door cannot be opened mid-flight. The pilot controls the mechanical door locks from the cockpit, and handles cannot be moved until the pilot disengages these locks. This is why you may hear a pilot announce that the doors have been set to manual after landing. Door functions may also be aided by pneumatic or hydraulic systems to ensure safety and operability.
With the use of natural forces and mechanical technology, aircraft doors should be the least of one’s worries when flying on an aircraft. Aircraft engineers ensure the safety and integrity of each and every aircraft component
through years of design, testing, and improvement. In the coming years, pressurization ability and safety will only improve to bring more comfort to passengers, even while at 38,000 feet in the air.
Posted on February 7, 2020