Aircraft assisted escape systems 7340 Flashcards
describe the ejection gun components and operation
- developed to provide the initial power to eject the seat.
- compromises cylindrical tubes with a single percussion fired initiator and multiple face fired secondary cartridges which gradually combine to increase the rate of acceleration.
- incorporates guide rails which locate the seat slippers attached to the main seat assembly.
- the ejection gun is secured to the aircraft structure via mounting brackets
describe the drogue parachute operation and components
- one (or more) small parachutes deployed prior to the main parachute; it is designed to slow and stabilise the ejection seat after exiting the aircraft.
- typical drogue chutes are between 2 and 5 feet (0.6 and 1.5m) in diameter.
- drogue chutes are then released to deploy the main parachutes
describe the drogue gun and components
- the drogue gun fires a steel rod (or uses a rocket nozzle) to deploy the drogue chute(s) away from the seat vortex to prevent the drogues from becoming entangled.
- incorporates a delay to ensure the seat has cleared the cockpit
describe the scissor shackle operation and components
when the time release unit cartridge fires, the scissor shackle plunger retracts and allows the moveable jaw of the scissor mechanism to open and release the personal parachute from its container
describe (barostastatic) time release unit and components
- tripped by a static line as the seat rises, it imposes a clockwork delay before releasinga plunger in the scissor shackle while simultaneously unlocking the seat harness to free the occupant from the seat.
- the barostatic capsule prevents the TRU from operating at heights above 10,000ft to help ensure occupants safety
leg restraint system
garter leg restraints are designed to ensure that the pilots’ legs are drawn back and held close to the seat pan during and after ejection to avoid injuries to the limbs
duplex drogue system
a pair of drogue parachutes are deployed in sequence to lessen the shock on the system from a single, large drogue opening at speed
canopy clearance system
- the emergency canopy jettison system provides the capability to ballistically jettison the canopy in the case of an emergency.
- typically the canopy is blown upwards and backwards by explosive charges and then relative wind clears the canopy from the path of ejection.
- later this innovation was adapted to include the option to fragment the canopy using explosives or provide canopy breakers on the seat structure to physically punch through the canopy
personal equipment connector (PEC)
- the PEC consists of 3 interlocking parts - the aircraft portion, the seat portion and the man portion.
- via a simple, single action, the PEC enables connection and disconnection from services during routine entry and exit, as well as during the ejection sequence.
multi-tube rocket pack
- the rocket pack ignites as the ejection gun nears the end of its extension and raises the seat to a height sufficient for a safe parachute descent.
- it incorporates an initiator charge to ignite the rocket propellant instantaneously.
remote rocket firing system
- the remote system contains a coiled static line which is drawn out as the seat rises to pull out a sear and fire a cartridge.
- the resultant gas travels down a tube to ignite the rocket via an initiator
pitch control unit (PCU)
a calibrated handwheel on the PCU is designed to adjust the angle of thrust from the rocket motor to ensure that it passes through the centre of gravity of the ejected mass: (occupant + ejection seat)
Harness power retraction unit (HPRU)
- the power retraction system is designed to automatically place the occupant in the most favourable position for ejection - sitting upright so that adjacent vertabrae are in line and square with each other.
- however, during normal operations, the system does permit the occupant complete freedom of movement to reach forward and twist as required
detachable seat pan/bucket
- seat pans/seat buckets are secured to thread studs on the seat structure to allow for easy access.
- adjustable in height via a seat raising actuator
trip rods
- trip rods are telescopic linkages that provide a rigid alternative to operating lanyards and which remove the associated snagging hazards.
- trip rods attach between a cockpit hard-point and a seat mounted component (e.g. BTRU, drogue gun) to transfer the initiation impetus when the set starts to rise
arm restraint lines
provide arm protection during ejection.
the arm lines are routed from the quick release box (QRB) through snubbers and guillotine to the arms of the flight jacket.
guillotine automatically cuts the arm lines at man/seat separation
automatic liferaft inflation unit (ALIU)
- the ALIU automaticlly inflates the liferaft on entry into water (fresh or salt).
- a manual facility also exists to allow the ejectee to inflate the liferaft on land (as a location aid or basic shelter) or to cater for ALIU failure
describe a helmet transmitter unit
a magnetic field generator which detects a reciever in the rear of the helmet and gives an output proportional to helmet displacement
quick release box
automatic release following salt water immersion
headpad
contains head protection device (NPD)
ASE handle
armed/safe/egress handle prevents seat initiator (SI) from operating in the safe or egress position
in armed position allows SI firing mechanism to operate normally during either manual or automatic ejection sequence
upper aerosurface
front edge deploys at catapult separation and rotates to one of two different angles depending upon airspeed.
prevents the seat from pitching forward with smaller mass aircrew
same as PEC
Service connection package
connects the OBOGS,
anti-g supply
FAS supply
communications
BOS
automatics back-up unit location
ABU is a mechanical backup system for parachute deplyoment harness release, (replaces man/sep facility)
electronics sequencer
thermal battery
monitors the state of two start switches and thereafter controls the ejection sequence
FAS
filtered air supply provides cockpit air for visor demist, head cooling and breathing air supplies during cockpit checks/engine start up
air vehicle interface disconnect unit (AIDU)
disconnects all the ballistics, pneumatic and electrical interfaces for the seat.
mk 16 ejection sequence (initiation )
aircrew manually pulls firing handle to fire 2 seat initiator (SI) cartridges
or
ejection seat firing module fires auto eject unit cartridge to mechanically fire SI carts
mk 16 ejection seat begins to rise
electrical disconnection of AIDU initiates emergency location trnsmitter and is used to zeroise flight software
Safety conditions
safe for maintenacnce
safe for parking
safe condition
flight condition
safe for maintenance
in this condition it is safe to carry out work on or around the AAES if;
- A/C is prolonged unserviceability
- for schedule maintenance
- any maintenance activity that involves working in the vacinity of the AAES
- parking of the A/C in an A/C maintenance hanger,
safe for parking
required at all times exept when it is in the other conditions including a rapid crew change
it is safe to enter cockpit, provided that the safety instruction relevant to the particular aircraft type are followed
no maintenance, other then flight servicing can be carried out
safe condition
on AAES where safe for maintenance and safe for parking are no different
it is safe to carry out work on or around the AAES
flight condition
- an AAES is in flight condition when all safety devices have been removed
- only in flight condition before taxiing or after landing
maintenance personnel may assist
when operating from hardened aircraft shelter (HAS) or similar AAES remain in safe under cover
personnel must not enter cockpit if AAES are in flight condition
