Aircraft assisted escape systems 7340

Question 1

describe the ejection gun components and operation

Answer 1

• 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

Question 2

describe the drogue parachute operation and components

Answer 2

• 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

Question 3

describe the drogue gun and components

Answer 3

• 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

Question 4

describe the scissor shackle operation and components

Answer 4

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

Question 5

describe (barostastatic) time release unit and components

Answer 5

• 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

Question 6

leg restraint system

Answer 6

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

Question 7

duplex drogue system

Answer 7

a pair of drogue parachutes are deployed in sequence to lessen the shock on the system from a single, large drogue opening at speed

Question 8

canopy clearance system

Answer 8

• 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

Question 9

personal equipment connector (PEC)

Answer 9

• 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.

Question 10

multi-tube rocket pack

Answer 10

• 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.

Question 11

remote rocket firing system

Answer 11

• 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

Question 12

pitch control unit (PCU)

Answer 12

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)

Question 13

Harness power retraction unit (HPRU)

Answer 13

• 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

Question 14

detachable seat pan/bucket

Answer 14

• 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

Question 15

trip rods

Answer 15

• 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

Question 16

arm restraint lines

Answer 16

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

Question 17

automatic liferaft inflation unit (ALIU)

Answer 17

• 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

Question 18

describe a helmet transmitter unit

Answer 18

a magnetic field generator which detects a reciever in the rear of the helmet and gives an output proportional to helmet displacement

Question 19

quick release box

Answer 19

automatic release following salt water immersion

Question 20

headpad

Answer 20

contains head protection device (NPD)

Question 21

ASE handle

Answer 21

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

Question 22

upper aerosurface

Answer 22

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

Question 23

same as PEC

Service connection package

Answer 23

connects the OBOGS,

anti-g supply

FAS supply

communications

BOS

Question 24

automatics back-up unit location

Answer 24

ABU is a mechanical backup system for parachute deplyoment harness release, (replaces man/sep facility)

Question 25

electronics sequencer

Answer 25

thermal battery

monitors the state of two start switches and thereafter controls the ejection sequence

Question 26

FAS

Answer 26

filtered air supply provides cockpit air for visor demist, head cooling and breathing air supplies during cockpit checks/engine start up

Question 27

air vehicle interface disconnect unit (AIDU)

Answer 27

disconnects all the ballistics, pneumatic and electrical interfaces for the seat.

Question 28

mk 16 ejection sequence (initiation )

Answer 28

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

Question 29

mk 16 ejection seat begins to rise

Answer 29

electrical disconnection of AIDU initiates emergency location trnsmitter and is used to zeroise flight software

Question 30

Safety conditions

Answer 30

safe for maintenacnce

safe for parking

safe condition

flight condition

Question 31

safe for maintenance

Answer 31

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,

Question 32

safe for parking

Answer 32

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

Question 33

safe condition

Answer 33

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

Question 34

flight condition

Answer 34

• 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