Armament system

External stores are carried on seven wing stores: Four under the wing, one on the center line and one on each wing tip.

The under wing stations have pylons fitted for carriage of stores. Fitting of center line pylon is dependent on the type of store to be carried.

Pylon includes:

An ejector release unit which contains a bomb on station switch Nose and tail arming units Arming connectors Lanyard attachment points

Weapon control:

The store management system consists of:

2xweapon control panels (one in each cockpit Weapon Programing Unit Hands on throttle and stick control Master armament safety switch MASS safe indicator Emergency jettison switches Armament junction boxes Armament weight on wheels micro switches

The SMS:

Store management systems selects and control the release of pylon stores.

Provide signals for bomb fusing Control and fires rocket missiles and Aden gun.

Gun installation:

The gun is attached to a gun mounting cradle, inverted and assembled to a gun pod cradle and fitted in a streamlined pod.

Gun Pod:

The gun pod is attached to the bottom surface of the wing structure on the aircraft centerline and includes:

An ammunition box for Gun An ammunition feed cute A used case ejection tube A gas purging system An electrical cable assembly

(An ammunition box carries up to 100 rounds in a belt and is poisoned behind the gun)

An empty gun pod can be converted in to a baggage pod.

Power supply:

Electrical power supply to the armament control circuit through the no 1 armament junction box. The input supplies to the no.1 armament junction box are from the no.1 battery busbar, the 28 volt DC essential services busbar and the 115 v B and C phase, 400 Hz a.c. busbars. The d.c. supplies are switches through the weight on wheels microswitches on the aircraft take off. Test switches are fitted to perform a ground test of the system. Armament busbars A and B status indicators on the WPC. In each cockpit show when the armament power supplies are available.

With the MASS set to live and weight on wheels, 28 v d.c. is supplied to the WPU. When the aircraft takes off , weight on wheels microwitches provide a return path for the 28 v d.c. to energies the coils of the A and B no. 2 armament supply relays to power up the A and B armament busbars.

Description and operation :

Introduction: the aircraft has seven stations on whitch a variety of stores can be carried . the station are shown in the figure

The store management system (SMS) control the selection and release or firing of stros losded onto pylon stations and wing tips. The weapons control panel (WCP) is used to set up the weapon pacakages and the head up display shows the attack symbology.

The SMS consists of the items that follows:

A WCP in each cockpit WCP programing unit No.1 and no.2 armament junction boxes A master armament safety switch A MASS safe indicator A armament weight on wheels microswitches A store emergency jettision switch in each cockpit Switches and control on the control column handle(CCH) and throttle control TCH) in

each cockpit these switches and control are part of the hands on throttle and stick (HOTAS) control system

Armament ground test switches

The SMS is operated through the WCP, the weapon related HOTAS switches the related MFD format, the MASS and the emergency jettison switches.

Related systems:

The SMS interface with the following systems:

Flap control system Landing gear system Electrical power supply and distribution Internal lighting Central warning system Communication control system Data bus system Display and mission computer.

Control and displays Video monitorin and recording system Gun if fitted

Weapon control unit:

General: the WPU is fitted on the mounting tray at frame 7 and the access is through the door 113A. The WPU is fitted to the mounting tray with the two knurled nuts which engage with corresponding hooks of the front face of the WPU. The WPU respond to the SMS input from the WCP and CCH in each cockpit. Weapon inventory panel (WIP) codes are entered with the thumb wheels on the front face of the WPU. As only one WIP code is provided for wing tip, outboard and inboard stations these weapons must be loaded symmetrically. When an invalid WIP code is entered ILL WIP and the station position where the invalid code has been entered as shown on the WCP LCD. There are 9 thumbwheels on the WPU which are identified left to right as follows

Wingtip one thumbwheel Outboard two thumbwheel Inboard two thumbwheel Centerline 2 thumbwheel Gun RND x 10 two thumwheels

Armament junction box:

The no. 1 armament junction box is located in the rear equipment bay and access is through door 121A. 10 bolts attach the unit to the forward face of the frame 12. 8 electrical receptors on the unit are used to connect the unit to the SMS.

The armament junction box contains the component that follows:

WPU armament supply ‘A’no.1 relay is the first stage in the application of electrical power to armament busbars A. when MASS is set to LIVE, 28V d.c. from the no.1 battery busbar is supplied to the relay coil. The relay energizes and supplies 28V d.c. from the no.1 battery contacts of the WPU armament supply ‘A’ no.2 relay.

b. WPU armament supply ‘A’ no.2 relay:,

WPU armament supply no.2 relay controls the application of power to armament busbar A. When the MASS set to LIVE the aircraft is weight off wheel or the armament test 1 switch is operated, 28 d.c. from the no.1 busbar is supplied to the relay coil. Supply ‘A’ no.1 relay, through close contacts A2-A1 and B2-B1, to armament busbar A.

c. WPU armament supply ‘B’ no.1 relay:

WPU armament supply ‘B’ no.1 relay is the first stage in the application of electrical power to the armament busbar B. when the MASS is set to LIVE, 28 volt d.c. from the essential services busbar through closed contacts of the WPU armament supply ‘B’ no.2 relay.

d. WPU armament supply ‘B’ no.2 relay:

WPU armament supply ‘B’ no.2 relay controls the application of power to the armament busbar B. when the MASS is set to live, the aircraft is weight off wheels or the ARMAMENT TEST 2 switch is operated, 28V d.c. from the closed contacts of the WPU armament supply ‘B’mno.1 relay, through closed contacts A2-A1 and B@-B1 to armament busbar B.

e. pylon and wing tip power relay:

The pylon and wing tip power relay control the supply of 28v d.c. and 115v a.c. to the right outboard, left wingtip, wingtip and left outboard pylons. When the store require electrical power the WPU energizes the related relay for that pylon or wingtip.

f. Wingtip AAM fire relay:

The wingtip AAM fire relay control the supply of the air to air missile fire signal to the right wing and left wingtip pylons.

h. Gun vent relay:

The gun vent relay is energized when a ground signal is supplied to the coil of the relay from the closed contacts A2-A1 of the gun select relay. Armament busbar b supplies 28v d.c. through close contacts C@-C! of the gun vent relay to the coil of the vent open relay.

i. Gun arming relay:

The gun arming relay is energized, when a gun arm signal is supplied to the relay coil from the WPU.

g. Gun firing relay:

The gun firing relay controls the firing of the gun. The relay is energized when the gun fire signal is supplied to the relay coil from the WPU, through closed contacts A2-A1 of the vent open relay.

h. Vent open relay:

the vent open relay is energized when 28v d.c. is supplied from armament busbar B, to the coil of the relay through closed content C2-C1 of the gun vent relay and the gun vent actuator shorting link.

Armament junction box:

The armament junction box no.2 is location in the rear equipment bay and accesss is through the door 121A.Four bolts and washers attach the unit to the rear of the rear seat frame. Two electrical receptors connect the unit to the recepticles connect the unit to the SMS. The no.2 armament system contains the following components that follows:

Chaff and flare MASS/WOW relay ACMI pod control relay

Ground safety devices and indicator:

To prevent the accidental firing, jettision or release of stores when the aircraft is on the ground, the SMS has the safety devices that follow:

MASS MASS safe indicator MASS safe supply switch Armament weight on wheels microswitches A nose undercarriage uplock micro switch

Additional ground safety devices are fitted to the store suspension equipment and store loaded to the aircraft.

Emergency jettison switch:

There is emergency jettison switch in the each cockpit, to the left instrument panel. The front cockpit is on the MASS jettison control panel and the rear cockpit switch is on the jettison control panel. The switch is a shrouded black and yellow stripped back lit panel identified clear aircraft. . Stores are jettisoned when when the armament busbars are energized. When either of the emergency switch is pushed momentarily pushed, all jettison able stores are jettisoned. Air to air missiles is not jettisoned as the ejector release units are fitted with dummy cartridge holders when the air to air missiles are used.

Cockpit switches and controls:

The aircraft is designed to use HOTAS. The switches associated with the SMS air to air weapon delivery, air to ground derivery,air to ground weapon delivery and gun firing are on the TCH and CCH in each cockpit.

Control column handle:

The HOTAS switches, on the CCH, associated with weapon release are as follows:

1. Air to air select switch: It is a thumb operated four position switch and spring loaded to Centre off position. The switch operates as follows:

Momentary push forward select air to air missile mode. A second push in forward commands SMS to reject the current missile and select the next available missile for the release.

2. Air to ground weapon select:

It is thumb operated five position switch spring loaded to the center off position.

Momentary push forward select air to air bombs and rocket mode. A second push in forward commands SMS to reject the current bombs and rocket mode and select the next available bombs and rocket mode for the release.

Weapon selection reset switch:

The weapon selection reset switch when momentarily push commands SMS to exit weapons mode and reset the system to general navigation mode.

Weapon release trigger:

The weapon release initiates release of the selected weapon , when all the condition that follow are met:

MASS is set to LIVE, the aircraft is weight off wheels and therefore armament bushbar power is available.

LATE ARM is selected on WCP. This condition is met the ARM legend on each WCP is lit and legend LIVE is shown on WCP LCD.

Power supply:

Power supply to the SMS are from the:

a.c. junction box right supply panel left supply panel

the SMS related fuses and circuits breaks are given in table 2

The a.c. junction box:

The a.c. junction box is located in the front equipment bay b/w frames C& D and is access door is 21A. the junction box is used to supply:

I. 115v A-phase 400 Hz a.c.II. 115v B-phase 400 Hz a.c.

III. 115v C-phase 400 Hz a.c.IV. 200v 3-phase 400 Hz a.c.

Armament stores carriage and release system:

Introduction:

The aircraft is equipped with four under wing pylons which provide for

The carriage and release of practice bombs, Mk.8.1, Mk82 and Mk83, free fall bombs, Mk82 smakeye retarded bombs and GBU-12 E/B laser guided bombs(all pylon stations)

The carriage of the fuel tanks(inboard pylon only) The carriage and release of LAU-51 and MANTRA 155 M/N and F$ rocket launchers The carriage and release of Matra R550, magic-2 and sidewinder missiles(outboard only)

In addition, it is possible for sidewinder missile to be carried and fired from wing tip stations.

It is possible for an Aden 30mm gun pod to be attached to bottom surface of the main plane on the fuselage centerline.

When a centerline pylon is fitted, it is possible for a Mk.81, Mk82 or Mk 83 ,free fall bomb or a GBU-12 E/B laser guided bomb to be carried in that position.

Access panels and fairing:

Access panel and fairing have the panel or fairing, number written on the inside. They use from in place weather proofing seals. When the inboard pylon is fitted, wing access panel 543(left)

And 643B (right) are replaced with access panel 543(left) and 645( c ). Panels 543(left) and 643 (r) have a cutout and grommet to let the rear electrical cable through. When outboard pylone is fitted, wing access panel 533(left) and right removed for storage and fitted on the removal of the pylon.

Inboard pylon:

The main attachment is a high tensile steel front fitting bolted to the structural members. Bolts through two diagonally opposed holes in the front fitting attach the pylon to the main plane. When the attachment of the pylon is completed, the front fitting is are locked with wire and covered with fairing 914 AP and 914 AE .

The rear of the pylon is attached to the attachment bracket with a rear attachment pin. A lug on the rear attachment bracket engages with the pylon rear attachment. They are held with the rear attachment pin, the pin is fitted with its head to the rear, it is held in position with the

access panel 915 D. A wedge, fitted b/w the rear attachment and the rear attachment bracket, prevent the vertical movement of the pylon. The wedge is held in position with a self-locking nut. The fuel and air valve is fitted for use with external tank.

Role changing facility:

It is possible to fit additional wiring assembly when the pylon is required to carry a missile. The role change connector is connected to the aircraft wiring through a receptacle which is mounted on a bracket.

The bracket assembly is fitted externally to the right side of the pylon and covered with a fairing. The electrical connection to the missile is through the bottom of the pylon. To make this connection, a pylon and its four securing bolt must be removed. When fitted, this role change connector is attached to the aircraft structure with a lanyard.

Fuel and valve:

The fuel and air valve assembly is fitted to the rear of the front fitting. The fuel and air connectors extend above pylon top plate and connect with connectors in the main plane. The valve base plane and the valve orifice sleeves are bolted to the pylon bolted rib. This area makes a recess under the rib which is connect with the panel no 915 when the external tank is not fitted. Access tom the fuel and air valve assembly is through panel 915B on the side plate.

Out board pylon

The main attachment is a high tensile steel front fitting bolted to the structural members. Bolts through two diagonally opposed holes in the front fitting attach the pylon to the main plane. When the attachment of the pylon is completed, the front fitting is are locked with wire and covered with fairing 934 CP .

The rear of the pylon is attached to the attachment bracket with a rear attachment pin. A lug on the rear attachment bracket engages with the pylon rear attachment. They are held with the rear attachment pin. The attachment pin is locked in the position with locking pin. Access is through 935 DP and 935 DE.

Role change facility

It is possible to fit additional wiring assembly when the pylon is required to carry a missile. The role change connector is connected to the aircraft wiring through a receptacle which is mounted on a bracket.

The bracket assembly is fitted externally to the right side of the pylon and covered with a fairing. The electrical connection to the missile is through the bottom of the pylon. To make this connection, a pylon and its four securing bolt must be removed. When fitted, this role change connector is attached to the aircraft structure with a lanyard.

Centerline pylon

The centerline pylon is different from the inboard and out board pylon in shape, structure and method of attachment.in the centerline pylon, the pylon junction box is located forward of the front attachment fitting. Access tom the junction box is by the removal of the captive access panel 922A on the left side of the nose. The pylon is attached to the aircraft by the front and rear fittings. The attachment fittings are machined steel parts and riveted to the front side plates and introduced transverse flanges. The flanges are drilled with two holes through which the attachment bolts pass. The holes in the rear fitting are set wider than those in the front fitting. When the centerline pylon is fitted, wing access panel 512 A and 570 A are removed for storage. A left fairing (922 CE) and right fairing (922 CP) assembly is fitted each side of the pylon and attached bolts to the land for the panel 512 A. On removal of the pylon and fairing assemblies, panel 512 A and 570 A are refitted.

Carrier bomb light stores:

The carrier bomb light stores 2000 is a dispenser for practice bombs. Each CBLS carriage 4 practice bombs, loaded in even no. and hung from the ejector release unit (ERU) equipped with an adaptor kit. Each ERU holds the body of a store in caliper to initiate the bomb release. When the CBLS is to remain empty or is in transit, dummy cartridge holders are to be fitted. It is possible for a max. of 4 CBLS dispensers to be carried symmetrically on inboard and/or outboard pylon.

Structure:

The CBLS structure includes:

A light ally semi cylindrical Centre section. Removable nose and tail fairing

The Centre section is riveted and bolted assembly, with attachment points for the four ERU. It includes:

A reduced top cover plate A floor panel Diaphragms Skirt members Mounting bracket for the associated electrical system components

Removable panels are fitted in the floor and a quick release spring is included in the top skin for the access to the role plug/safty break receptacle. The top cover houses suspension lug pockets and provide crutching areas for pylon sole plates and pylon ERU sway braces.

The nose and tail fairing, which provide aerodynamic cleanness, are welded and riveted assemblies. The tail fairing is filled with rigid polyurethane foam to prevent distortion from high aerodynamic forces.

Electrical system:

The CBLS has an aircraft electrical interface connector assembly with an auto-selector which distribute the firing pulses to the four ERU. The main firing firing line go through a role plug which, when act as a safety break panel, inside the spring loaded access door.there are Rad-Haz filters and limiting resistors in each ERU breech housing to prevent the ignition of the cartridge by indused electrical currents caused by external electromagnetic radiation.

Operation:

When the release of the practice bomb is selected via the store management system, the firing pulse is feed from the interface connector, through the role plug to the release input of the bomb auto selector.

Connectors within the auto selector output the firing pulse to the terminal 1 of the auto selector and the cartridge of the first ERU in the sequence. The gas generate operate the ERU, to release the bomb. Subsequent firing go in the same way but the auto selector steps to release the bombs from ERU in the sequence that follow:

Left rear Right rear Left front Right front

Rocket launcher:

LAU-51 rocket launcher:

The LAU-51 reusable rocket launcher is able to carry and fire upto 19x2.75in rockets. It is possible for a max. of 4 LAU-51 rocket launchers to be carried symmetrically on inboard and outboard pylon. Linen dust covers are fitted to the front and the rear of the assembled launcher to protect it against the ingress of foreign objects. The covers are used when the launcher is in the storage or fitted to the aircraft. The covers must be removed before the aircraft takes off.

Structure:

The LAU-51 structure include:

Nose cone assembly Cylindrical Centre section A tail cone assembly

A nose cone assembly is a conical casting with 19 tubes which align with the centre section by means of screws. Each of the tube is numbered on the nose cone. Beneath each number there is a ‘v’ which must be located between the two of the rocket fins when a rocket is loaded.

Cylindrical aluminum section contain 19 rocket tubes any tube that has a rocket loaded on to it, has a blanking plug in the front end. Pair of suspension lugs are housed on the centre section along with the main electrical connector. At the rear of the central section there is a breaker switch.

The tail cone forms the rear fairing and is open ended to allow the gas produced during the rocket fairing to escape. The rear firing on the tail cone provides access to the SINGLE/RIPPLE and intervalometer switches.

Electrical system:

The power supply from the aircraft goes through an electrical connector on the top of the centre section of the LAU-51, through the breaker switch, intervalometer switch and SINGLE/RIPPLE switch to the rocket motors. When the safety pin is fitted in the breaker switch, it prevent the accidental ignition of rocket. Located on the rear bulkhead is two switches, one switch selects either SINGLE or RIPPLE fire while the other on, the intervalometer switch, act as another safety switch. When the intervalometer switch is set to L the electrical circuit to rocket is broken, immediately before flight, this switch is set to A.

Operation

When the rocket is selected to fired via a store management system, the firing pulse is fed from the electrical connector, through the breaker switch, the intervalometer switch and through the SINGLE/RIPPLE switch to either a single rocket motor or all of them. In the SINGLE mode, subsequent firing go the same way but the intervalometer steps the pulses to ignite the rocket one at a time. The SMS controls the number of firing pulses(set on the weapon control panel), sent to the launcher, therefore, the SINGLE/RIPPLE must set to SINGLE before flight.

Guided weapons carriage and release system

It is possible to load sidewinder, tactical or acquition missile to the aircraft at the store station that follows:

Left wing tip Left outboard pylon Right outboard pylon Right wing tip

It is possible to load Matra R550 magic, 2 tacticle or acquition missile to the aircraft at left and the right outboard pylon only.

The missiles are carried on launchers which are not jettisoned. Adaptor assemblies are fitted to interface the launchers with the outboard pylons. Adaptors are not necessary to interface the launchers at the wingtips, the launchers are attached to the wing assemblies directly.Ddummy cartridge holders are fitted to the ejector release unit, When the launcher, adaptor assemblies are fitted to the pylons.

Tactical missiles:

The tactical sidewinder and magic missiles are air to air guided missiles. They use passive infrared target detection and have proportional navigational guidance and a torque balance control system. AIM-9L sidewinder tactical missiles have an active optical target detector (AOTD).

Acquisition missiles:

The acquisition sidewinder and magic missiles include full functionality air crew training purpose. They do not have live rocket motor fitted. They are fitted with an operational guidance control system and training umbilical connector(which disable the missile firing system)

Launcher and adaptor:

It is necessary to fit a launcher/adaptor assemblies to the outboard pylon when the missiles are to be loaded. When the missiles are to be loaded on the wingtip stations launchers are fitted directly to the wing structure.

Control system:

The switches and controls applicable to missile selection and launch are part of the store management system.

Magic missiles

It is possible to load two tactical and acquisition missile to launcher on the aircraft. Adaptor assemblies are fitted to interface with launcher with the outboard pylon. The complete assemble is attached to the pylon where the adaptor engages with an ejector release unit.

Operation

Missile preparation:

The missile requires 115v and 400 Hz a.c. and 400 Hz a.c. power supply for atleast 15 min before it is launched.

Missile prelaunch:

The missile seeker head scans around its bore sight position in a square pattern. When the seeker head detect an infrared source of sufficient energy, the missile lock to the source and generate an audio tone.

Fuel dip system:

Before launch the fuel dip test of off/on switch is said to on, this system reduce the fuel flow tom the engine fuel spray nozzle. When missile is launched it reduce the possibility of engine surge, caused with the injection of missile exhaust gases.

Missile launch

The missile is released as the trigger is pulled.

Side winder missile

It is possible to load two or 4 tactical and acquisition missile to launcher on the aircraft symmetrically. Adaptor assemblies are fitted to interface launchers with the outboard pylon. Adaptor are not necessary to interface the launchers are attached directly to the wing structure.

Missile preparation:

The missile requires 115v and 400 Hz a.c. and 400 Hz a.c. power supply for atleast 15 min before it is launched.

Missile target acquisition:

The missile generate an audio signal when the infrared target is missile seeker head field of view. This is an audio signal, variable in volume and pitch, that increase in volume the closer the target is to the centre of the missile seeker head field of view. When the target is acquired the lock button is selected to command the seeker head to lock the target missile lock to the target when missile lock to an infrared source, the audio tone changes the pitch.

Launchers:

Hangers on the missile engage with housing rails on the launcher and electro mechanical lock system holds the missile in position until it is launched. The launcher is made up of:

1. Front and rear fairing assemblies:

They are attached to the housing assembly and make up the aerodynamic nose and tail of the launcher.

2. Housing assembly: it makes up the main structure of the launcher to which other assemblies are attached.

3. Nitrogen receiver assembly:

It stores high pressure nitrogen/air to supply the infrared target detector in the missile.

4. Mechanism assembly:

It includes

a) nitrogen control valve

b) electromechanical control lock systemc) electrical harness assemblyd) safety switch

5. power supply assembly:

It is connected to the mechanism assembly. It provide electrical and nitrogen supply to the missile during captive missile.

Adaptors

Adaptors interfaces the launcher with the pylon ERU and wiring.

Harmonization

It is the process of aligning the aircraft navigation and sighting system, mounting trays, to give a high degree of system accuracy.

The initial harmonization is done during manufacturing, then the components are interchangeable without rehamonisation of the aircraft. Longitudinal fuselage datum(LFD) is reference point used to do the harmonization of the mounting tray, that holds the following units:

1. AHRS/GPS2. pilot display unit PDU3. INGPS

AHRS/GPS navigation sensor unit mounting tray: It requires harmonization whenever the accuracy of the system is in suspected. Angular variance data obtained from AHRS/GPS harmonization is entered into the AHRS/GPS through DCP and stored in NSU.

PDU mounting tray: : It requires harmonization whenever the accuracy of the system is in suspected or the mounting tray is removed. There are horizontal and vertical adjust to realign the PDU mounting tray to within the harmonization tolerances tray.

INGPS mounting tray: : It requires harmonization whenever the accuracy of the system is in suspected. Angular variance data, obtained from INGPS harmonization is entered into the INGPS through the DNC software.

Harmolign system:

Harmonization of the aircraft system is done with the metronor harmoline system. It consists of system that follows:

A military personal computer and associated cables: it shows the real time results of harmonization. It is powered from the main electricity 110v to 250v a.c. 50 Hz and 400 Hz. It has a built in hard drive to save the result of each procedure.

A camera with tripod and associated cables: it captures the image of the aircraft and sends it to the MPC. Image is refreshed each second to give precise position display of each AHP.

Four aircraft harmonization pad and associated cables: AHP hold an array of the LED, that are viewed by camera. Position of LED array is calculated by NPC and the position of AHP and LRU mounting tray on which it is attached can be accurately determined.

Three harmonization packaging cases

An accessories kit include a space camera and LRU tray replicator needed for doing a checkup of the AHP.

The LFD aircraft harmonization pad: the location points give the LFD of the aircraft which is set by manufacturer

AHRS/ GPS aircraft harmonization pad: it is fitted to AHRS/GPS navigation sensor unit mounting tray. When NSU has been removed.

PDU AHP: it is fitted to PDU AHP navigation sensor unit mounting tray. When NSU has been removed.

INGPS AHP: it is fitted to INGPS AHP navigation sensor unit mounting tray. When NSU has been removed.