When a crew member pulls the ejection handle or lowers the face curtain, a precisely timed sequence is triggered that jettisons the canopy and propels the seat out of the aircraft within four seconds.

Pulling the handle fires an explosive cartridge in the catapult gun, launching the seat along guide rails. A leg‑restraint system activates immediately to protect the pilot’s legs from debris, while an underseat rocket motor lifts the crew to a safe altitude. According to Goodrich Corporation—an established manufacturer of ejection seats for the U.S. military and NASA—this force remains within normal human physiological limits.

Before the seat can launch, the canopy must be cleared. There are three common methods:

• Lifting the canopy – Explosive‑filled bolts detach the canopy, and small rocket thrusters on the forward lip push it out of the ejection path. (See Herker’s site for detailed explanations.)
• Shattering the canopy – A detonating cord or charge breaks the canopy into fragments that are swept away by the airflow, eliminating the risk of collision.
• Explosive hatches – Aircraft without canopies use explosive bolts to blow a hatch open, providing a clear egress.

The seat, parachute, and survival pack are ejected together. Models like Goodrich’s ACES II feature a fixed rocket motor that, after the crew clears the cockpit, pushes the seat another 100 to 200 ft (30.5 to 61 m) to avoid striking the tail. As of January 1998, the ACES II system had been used in 463 worldwide ejections, with a 90 % success rate and 42 fatalities reported by the U.S. Air Force.

After exiting the aircraft, a drogue gun fires a metal slug that deploys a small drogue parachute from the seat’s top. This slows descent and stabilizes trajectory. An altitude sensor later pulls the main parachute from the pilot’s chute pack, and a seat‑man separator motor releases the seat. The crew then descends under the main parachute, completing a safe landing.

Modes of Ejection

The ACES II system determines the ejection mode based on altitude and airspeed, measured by an environmental sensor and recovery sequencer. The sensor monitors the seat’s altitude and airspeed via pitot tubes, which gauge airflow velocity. Depending on the data, the sequencer selects one of three modes:

• Mode 1 – Low altitude (<15,000 ft) and low speed (<250 knots). The drogue parachute does not deploy.
• Mode 2 – Low altitude (<15,000 ft) but high speed (>250 knots).
• Mode 3 – High altitude (>15,000 ft) at any speed.

These modes ensure optimal performance across varying flight conditions, maximizing crew survival.