Well, can you open an airplane cabin door inflight or not? Or an overwing emergency exit door for that matter?
Updated July 25, 2020.
Whether it is possible to open that airplane door inflight or not is probably the single most asked question I get from my passengers!
No, an airplane door on a pressurized cannot and will not open inflight!
Passengers’ unfounded fear of the airplane door opening in flight
The passenger’s lack of knowledge or fear of the unknown compounds the fear around this subject. The news media is also guilty of sensationalizing relatively minor events that were no real threat to flight safety.
That’s how they keep us glued to their news channel!
A pressurized airplane door uses two different technologies incorporated into one door
For the purpose of this discussion, and to keep things simple, we will be talking about the technical aspects of the workings of Boeing doors. There are some differences with Airbus-doors:
The airplane door inflight on a pressurized airplane uses a safety-combination of two ingenious technologies. These dual technologies incorporated into one design are:
- Air pressure-sealed (plug door) technology, and
- Mechanical lock technology.
1. Air pressure-sealed door technology, called a “plug door”
The plug door technology is what’s preventing you from opening a pressurized airplane door inflight.
A pressure-sealed door (plug door) is a door that has been designed to seal itself by utilizing an air pressure differential between the inside and the outside of the airplane.
The plug door relies on the airplane’s cabin pressure to keep it shut.
These doors are referred to as “self-sealing doors”.
The higher air pressure inside the cabin while inflight keeps the door snuggly sealed to the airplane body.
The airplane’s pressurization is designed to be fully released at touchdown, by the design of landing gear ground sensors, also referred to as “ground shift mechanism”.
Why the shape of a pressurized airplane door is designed like a wedge
A wedge-shaped door is a door designed to seal shut like a cork on a champagne bottle. Picture the outside of the bottle representing the cabin. then picture your hand pushing the cork into the bottle representing cabin pressure.
To open a pressurized airplane cabin door (or overwing emergency window) the first movement of the door must allow the door or window to open by moving INWARD, into the cabin, against current cabin pressure.
AFTER that it can be opened OUTWARD, away from the current cabin pressure to the outside.
How much force is required to open the cabin door at 37,000 feet to counteract the airplane plug door pressurization seal?
Let’s say you’re flying on a Boeing 767 and someone tries to open the cabin door at 37,000 feet. The cabin is pressurized at 6.5 pounds of air pressure per square inch.
A B767 door is approximately 74 inches by 42 inches (1.88m by 1.07m). That means 3,108 square inches of pressure is being exerted on that door to keep it shut!
6.5 pounds of pressure per square inch multiplied by 3,108 square inches of that door means that it takes 20,202 pounds of brute human pulling force to pry that door open inflight!
An African bush elephant weighs an average of 13,000 pounds.
Do you know any human being able to pull the weight of almost two elephants laying down on the ground?
Well, that’s how much strength a human being would need to have to pry that cabin door open from its solid grip on the airplane body!
2. Mechanical door lock technology
The mechanical lock mechanism is simply there to unlock and lock a door shut whether you are in a pressurized or unpressurized airplane or not.
The procedure is done with the help of plugs, handles, hooks, locking mechanisms, and other mechanical parts.
Mechanical door purpose
The mechanical door parts work in conjunction with the plug door design described above.
- Moving the door handle or the latching mechanism only releases mechanical-type locks.
- Some doors have pneumatically assisted mechanisms.
- The purpose of these locks is to keep the doors locked when the airplane is not pressurized or on the ground.
- We need the mechanical locks to keep the door secured shut when not pressurized.
- It also allows you to open the doors and the emergency over-wing exits during a ground emergency, or deplaning through the doors on the ground.
- Operation of the door mechanics also leads to the automatic activation of the emergency slides, when armed with the door open.
- Of course, the mechanical locks also work in the air. But in the air, they no longer function as the principal means of keeping the doors securely shut. As you know by now, cabin air pressure is the principal mechanism keeping the door sealed and locked in flight.
- In other words, cabin pressurization assumes the role of “the principal safety guardian of the door” in flight.
Opening the door at low altitudes when the cabin pressurization is low
Some articles written on the subject are questioning what would happen if someone tried to open the door at a low altitude of let’s say 2,000 feet.
Here’s your answer:
The cabin pressure, even at a low psi of let’s say at an almost un-pressurized airplane of 1.3 psi would still require 4,040 pounds of human pull-force to get that 3,108 square-inch Boeing 767 door that we talked about earlier to open!
Not even Arnold Schwarzenegger could get that door open, using his Terminator’s muscles!
Over the years I’ve had a couple of cabin pressurization malfunctions where the pressurization would not completely release after landing. Even with a tiny bit of cabin pressurization left, even well below where pressurization goes to at the moment the wheels leave the ground on takeoff was it impossible to even crack the door open!
So, can you open the cabin door at low altitudes? No, you cannot!
Airplane door opening video
Different airplane manufacturers and different airplane types have varied door designs, workings, and mechanisms, such as Airbus aircraft. For example, A320 doors are not plug-doors. Instead, the cabin pressure is applied by striker pads on arms that are part of the door structure.
How does an airplane maintain the cabin pressure keeping the door safely shut in flight?
The yellow arrows in the picture above show the cockpit control panel sections for the pneumatic, pressurization & air conditioning systems on the overhead cockpit panel of a Boeing 757 (B757).
Cabin pressure goes to work immediately when you lift off from the runway. Sensors in the wheels tell the airplane that you are no longer on the ground.
That ensures your safety and health from someone being able to open the door in flight.
Air passenger knowledge breeds air passenger confidence
So, the next time you see that news flash about yet another passenger trying to open an airplane door in flight you can consider yourself an expert on the subject.
If you have comments or questions, please contact us here.
Featured Image: Airbus.