Ejection Systems Crew members fire the seats by pulling up on: –arm rests –handles between legs –face curtain behind head Rescue personnel should be aware that efforts to remove pilots may activate the ejection system unless it is safetied.
Ejection Systems Seats are safetied by interrupting the firing sequence, pinning, or cutting the initiator hose. It may take several pins to safety a seat. In cutting hydraulic lines be sure to completely cut the line. Hands on training is necessary to become competent and confident in seat safety procedures.
Canopies Canopies are designed of a metal framework around a Lexan™ covering. There are 3 basic types of canopies: –Sliding –Clamshell, and –Hinged The sliding and clamshell are the most common.
Canopies Canopies are opened normally, either: –Pneumatically –Electrically –Hydraulically –Manually Most military aircraft will have canopy controls on the exterior of the cockpit.
Canopies In Emergencies canopies may be jettisoned. This may also be done from a panel on the side of the aircraft or by the flight crew. In jettisoning the canopy is fired by an explosive device away from the aircraft. Canopies should only be jettisoned if absolutely necessary. Jettisoning by ignite fuel vapors
Propellant Actuating Devices Ejection seats and canopies use Propellant Actuating Devices to initiate their function. Most require altitude and velocity to operate, though some have zero-zero capability. They are: Canopy removers, Initiators, Rotary actuators, Thrusters, Explosive Squibs and Seat Catapults.
Canopy Removers Generally they are gas powered telescoping devices that forcefully jettison the canopy in and emergency. Expanding gases force the telescoping tube to extend and remove the canopy.
Initiators Initiators are cylindrical shaped devices that provide gas pressure required to START a sequence of events in the ejection process. When the initiator pin is pulled a cartridge is fired which in turn fire the initiator. Hot gases flowing through tubes or hose cause the canopy or seat to eject.
Rotary Actuators They perform various mechanical functions in the aircraft. They are activated by the gas pressure from the initiators or by electrical current. As part of the ‘Canopy Remover pad Release” system they forcibly remove the crew member from the seat after ejection.
Thrusters Thrusters are gas-operated devices that unlock or reposition various units in the escape system. For example they unlock canopy latches just before jettison and move the seat and leg guards into position prior to ejection.
Explosive Squibs Explosive squibs are small metal tubes closed at on end and crimped with a rubber plug on the other. They provide an ignition source. Flash-vented squibs emit a flame to ignite rocket motors. Closed-end squibs are use in explosive bolts and explosive release mechanisms.
Seat Catapults Catapults are telescoping ejection devices used in the emergency ejection of crew members. There are two types: –Cartridge which propels the seat with enough force to clear the aircraft. And, –Rocket motor which provides enough thrust to make sure the crew member clears the fast moving aircraft.
Emergency Shutdown Procedures These vary from aircraft to aircraft. The most common procedure requires: –Pull the throttles back to IDLE position by lifting past a detent. –Activating the fire control system/s for the aircraft engines if available. –Shutting down the batteries. –Batteries should always be done last because some of the other functions may require electricity.