Physics Revisited : Can A Passenger Open An Airplane Door In Flight?

Given the news that an Alaska Airlines passenger was arrested yesterday at Portland International Airport after attempting to open an emergency exit door on-board Alaska Airlines flight 132, from Anchorage, this seems like a good time to revisit the issue of aircraft doors being opened in-flight. Can a passenger open a jet airliner’s door in flight?  Well … let’s go back to this blog post from the 13th of May 2011 and find out …

 

Over the past few weeks there seems to be an unusual frequency of stories regarding airline passengers attempting to open a commercial airliner’s door in flight.  The thought of a door opening in flight is scary, and with good reason … people fear being sucked out of a plane and the rapid decompression causing plane to crash … but the reality is that once a commercial airliner begins to pressurize during its taxi from the gate to the runway the it is virtually impossible for a passengers, or even a group of passengers, to open a door.

 

The physics of opening a door on a commercial airliner make the possibility of a passenger rotating the ‘open lever,’ and having the door open in flight highly improbable.  The majority of commercial passenger aircraft cabin doors are ‘plug’ doors. A ‘plug’ door is designed in such a way that the door’s physical size is larger than the hole it is placed into. In order to open a modern jet airliner’s door, the door must swing into the cabin before swinging out of the cabin.   Once an airplane begins to pressurize, the pressure around the seals around the door prevent the door from become dislodged, and on many aircraft requires a mechanical mechanism to physically lift the door.

 

What prevents a door from being pulled into the cabin to swing it out? According to Boeing “Since airplanes typically cruise above 30,000 feet, the air pressure inside the plane is much greater than the pressure outside — and that pressure differential makes it impossible to open the door, even if somebody wanted to do such a thing.”

 

Regarding the pressure holding a cabin door in place, Karlene Petitt, a veteran commercial airline pilot, says, “A group couldn’t open it because they don’t have the strength and ability. There is no way to harness the combined strength”

 

Gailen David, CEO of Jetiquette and a long time flight attendant with a major international airline, recalls two incidents that demonstrate the power of a pressurized cabin door. “I discovered just how impossible it is to open an airplane door before the cabin has been depressurized upon arrival at Chicago O’Hare. I went to open the door and it would not budge one bit. I advised the cockpit and they told me to wait about 15 seconds. Then everything worked perfectly. They had not depressurized the cabin.”

 

Gailen goes onto also discuss the dangers of pressurized cabin doors, “There was American Airlines A-300 incident in Miami in which a flight attendant was ejected from an airliner and died while the plane was on the ground and attempting an evacuation. The plane was not depressurized when the flight attendant lifted the lever…. however he left the lever in the open position and as soon as the cockpit crew depressurized the cabin, the door was suddenly able to open, but the sudden rush of pressure sent the flight attendant out the door as well.”

 

There is no doubt it is scary when a passenger runs towards a door and reaches for the ‘open lever,’ but there is no immediate danger to the passengers or aircraft, even if the ‘open lever’ is pulled and rotated.

 

The best advice comes from Gailen David … “Quick tip: Don’t touch the lever!”

 

Happy Flying!

 

@flyingwithfish

Comments

  1. So close yet such a fail! The 737’s NGs IE the 600 series and high do not use plug over-wing exit doors. What they do use is are doors that swing out and up. As they are not a plug door the pressure actually wants to push to door out. On the aircraft actually involved, a solenoid holds the door in place.

  2. John W. Butler,

    Once again you have shown your inability to read. If you have read my blog post you’d notice this “The majority of commercial passenger aircraft cabin doors are ‘plug’ doors. ”

    Yes, “the majority” which indicate that not all doors operate in this manner. The over wing exit doors you refer to actually have electronic locks, these locks prevent the exit doors from being opened while the engines blades are turning.

    I know you are always so eager to find errors, stir the pot and thump your chest, but it is more effective when you have actually read what you are commenting on. If you wish to debate the content of my post, feel free to take it up with Boeing.

    Happy Flying.

    -Fish

  3. John W. Butler,

    The content was not inaccurate, it did however discuss that “the majority of commercial passenger aircraft cabin doors are ‘plug’ doors. ” Which is factual, and is stated as such from Boeing and Airbus. I did not discuss the different types of doors, such as the 767 slide up door, the smaller over wing doors or the doors on aircraft such as the Dash-8.

    Happy Flying!

    -Fish

  4. I don’t understand. An airplane cabin is pressurized to about 7 or 8000 feet equivalent pressure. Or OK, maybe 6000 for the Dreamliner. In other words, the pressure inside the cabin is equivalent to the air pressure at about 7000 feet above sea level. So, when the aircraft is above 7000 feet, the pressure is higher in the cabin than it is outside.

    But below 7000 feet? Isn’t the pressure equivalent to whatever it is outside? Or is positive pressure maintained all the way to landing, actually increasing the pressure in the cabin to beyond the external pressure even when at sea level, until on the ground and “de-pressurized”.

  5. Bill G: Airliners are not perfectly sealed. They leak air as they fly. (That’s why they can only pressurize them so much. The Dreamliner can be pressurized more because it uses new materials that leak less.)

    I would assume that at 5000 feet, you’d be seeing an internal pressure greater than at 5000 feet outside, but less than ground level. It won’t leak as much as at 30,000 feet, though, because the pressure differential is less. So maybe you’d feel the equivalent of 3000 or 4000 feet. The relationship isn’t linear.

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