Take a Seat
Ejection seats are one of the most complex pieces of equipment on any aircraft. Some are made up of thousands of parts. The purpose of the ejection seat is simple. First, it must lift the pilot straight out of the aircraft to a safe distance. Then it needs to deploy a parachute to allow the pilot to land safely on the ground.

To understand how an ejection seat works, you must first be familiar with the basic components in any ejection system. Everything has to perform properly in a split second and in a specific sequence to save a pilot's life. If just one piece of critical equipment malfunctions, it could be fatal.

Photo courtesy Goodrich Corporation This ACES II ejection seat has a middle pull handle used to activate the ejection sequence.

Ejection seats are placed into the cockpit. They usually attach to rails via a set of rollers on the edges of the seat. During an ejection, these rails guide the seat out of the aircraft at a predetermined angle. Like any seat, the ejection seat's basic anatomy consists of the bucket, back and headrest. Everything else is built around these main components. The key devices of an ejection seat are the catapult, rocket, restraints and parachute.

In the event of an ejection, the catapult fires the seat up the rails. The rocket fires to propel the seat higher. And the parachute opens to allow for a safe landing. In some models, the rocket and catapult are combined into one device. These seats also double as restraint systems for the crewmembers both during an ejection and during normal operation.

Photo courtesy NASA An ejection seat is test-fired at NASA to analyze the seat's ability to perform a zero-altitude, zero-velocity ejection.

Ejection seats are just one part of a larger system called the assisted egress system. "Egress" means "a way out" or "exit." Another part of the overall egress system is the plane's canopy. It's the clear bubble-shaped top found on some planes. The canopy has to be removed - blown off really - before the ejection seat can be launched from the plane. This can be done in a few ways. For example, bolts filled with an explosive charge are detonated, detaching the canopy from the aircraft. Small rocket thrusters attached to the canopy push it out of the way of the ejection path. This process is known as "lifting the canopy." Another method is called "shattering the canopy." As the title indicates, an explosive is used to shatter the canopy. This is done by installing a detonating cord or an explosive charge around or across the canopy. When it explodes, the fragments of the canopy are moved out of the crewmember's path by the slipstream (the air gushing past the plane).

Photo courtesy U.S. Air Force Ejecting from an aircraft is rare, but pilots sometimes have to resort to pulling the ejection handle to save their lives.

Not all planes have canopies. A plane without a canopy will have an escape hatch built into its roof. Explosive bolts are used to blow the hatch just before the ejection seat is activated. This creates an escape portal.

Seats are activated through different methods. Some have pull handles on the sides or in the middle of the seat. Others are activated when a crewmember pulls a face curtain down to cover and protect his or her face.

Let's take a closer look at the technology.