Ask the Captain: Could a passenger open an emergency exit?

Question: Although I don't have a fear of flying, the information in your column is comforting. I was wondering how the emergency exit doors operate. I assume the doors can't be opened unless activated by someone, presumably the pilot. If so, what happens if that person or control is somehow incapacitated? Who or how else can the doors be opened?

-- Submitted by reader David, Kailua, O`ahu, Hawaii

Answer: Different airplanes use different style doors. These doors can be very complex, allowing security from opening in-flight while being easy to open should an evacuation be necessary. In addition, a slide is often attached or activated by the door opening.

Many of the larger doors are "plug"-type doors and are actually larger than the opening. This allows the pressurization to effectively lock the door in flight but when the handle is operated on the ground the door fits through the opening. Smaller overwing exits usually are plug-type, too. This requires that they be brought into the cabin as shown on the passenger safety cards. All the doors operate independently of each other. Flight attendants usually open the doors, but passengers should review the safety cards to ensure they know how a door is opened in the event it is needed. There is no activation from the pilots required.

Q: Why won't airlines reopen a gate once the door has been closed and before the flight takes off? I've had numerous instances where I arrive moments after the agent closes the door only to watch the airplane sit at the gate for upwards of 45 minutes before it actually pulls back.

-- Mike, South Carolina

A: Airlines vary in their willingness to open a door after departure time. The DOT watches and publishes on-time standings for the airline industry; as a result being on time is taken very seriously. Additionally the gate is usually scheduled for another airplane. If there is a delay for the departing airplane, it also affects the airplane waiting for the gate. This "domino" effect can multiply during the day, causing numerous delays. It is certainly frustrating to look at the airplane you are supposed to connect with and not be able to get onboard. It has happened to me several times too.

John Cox is a retired airline captain with U.S. Airways and runs his own aviation safety consulting company, Safety Operating Systems.