FIELD OF INVENTION
The Invention relates to mechanical engineering in general and in particular to an inspection component for inspecting loom assemblies for checking leakages at interface joints of immersed Drop Tank Loom assemblies. .
3. BACKGROUND OF INVENTION

In military aviation industries, such as drop tanks of aircrafts (including assemblies and subassemblies) manufacturing, the quality requirements are very stringent. In drop tanks, electrical loom assemblies are used for connecting to three Line Replaceable Units (LRUs) located inside Drop Tanks: Low Level Switch (1), Refuel-cum-Stop Air Valve (2) and High Level Switch (5) of Figure 1. These Looms are being fabricated on bench in Loom assembly Shop and subsequently finalized on Drop Tanks.
Brief Description of Drop Tank Loom Assemblies:
The Drop Tank Loom Assembly is an ‘Immersed Loom Assembly.’, and comprises of the following as shown in Figure 2:
1. One Main Electrical Connector (6) of Figure 2, forming the external.electrical interface to the aircraft, which is electrically wired to the following internal electrical interfaces:

a) One crimped type Electrical Loom Connector mating to the Refuel-cum-Stop Air Valve LRU (1a) of Figure 2.

b) One crimped type Electrical Loom Connector mating to the Fuel Low Level Switch LRU (1b) of Figure 2.

c) One crimped type Electrical Loom Connector mating to the Fuel High Level

Switch LRU (1c) of Figure 2. '
2. a) Portion of the loom wiring is jacketed inside the Raychem tubing 2(a) of Figure 2, and

b) Portion of the loom wiring is jacketed inside Metallic tubing 2(b) of

Figure 2, which are provided to prevent fuel ingress into the electrical wiring. Thus the wiring is not allowed to come in contact with Fuel.

3. One Heat Shrinkable Molded Transition 3 of Figure 2, allows loom from inside the Metallic Tubing to branch through the Raychem tubing to the Refuel- cum-Stop Air Valve LRU and Fuel Low Level Switch LRU.

Details of the Problem and Its Significance

During Air leak checks on equipped, fully built and sealed Drop Tanks, repeated leaks were observed from electrical loom assemblies (connectors /back shell & Boots, and Transitions) which involves: ■

A. Repetitive opening and closing of sealed Drop Tanks to identify the location of leak and rectify the same in the final stage of Drop Tank Build/ testing.

B. Opening of Drop Tanks for accessing these Loom Connectors, finding out the exact location of leaks, its rectification which involves removing, cleaning and reapplying the Raychem Adhesive over the leakage area, waiting for curing time, re-doing the leak checks and re-integration of the Drop Tank.

C. These reworks resulting in wastage of manpower, material resources and time which leads to large delay in production of Drop Tanks and affects the Quality of Drop Tank Build which is not conducive in present modern aviation industry.

Document US5375458A with a title “Leak test fixture” describes about a multi-port tool which tests for leaks in the seals of a control rod drive that has been removed from its housing. However present invention describes leak detection at interface joints of drop tank electrical loom assemblies.

Document US9909948B1 with title “Leak detection system" is a leak detection system for testing a tubing collar of wellbore tubing. The leak detection system is having a test unit with a control system for simultaneously controlling a gas system, a water system, a gas analysis system, and a tubing collar testing tool. This invention is not addressing the drop tank loom leakage issues.

4. BRIEF SUMMARY OF THE INVENTION
The purpose of present invention is to solve above mentioned problems and detecting leakages at interface joints in loom assemblies before its final integration in drop tanks.

To achieve the above objective, the present invention involves a design of Dedicated leak check test rig (Figure 3) for carrying out Air Leak check at the interface joints of Drop Tank loom assemblies at loom sub-system level to detect the snag before installing into the Drop Tanks.

In absence this leak test rig, the leaks are detected after the complete build of the Drop Tanks , which will then require major work involving opening of the Drop Tanks for rework i on Loom Assemblies.
5. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows Schematic Diagram of Drop Tank Loom Assemblies with Drop Tanks of fighter and Trainer Aircraft which consists of electrical system Refuel-cum-Stop Air Valve (1), Low level Switch (2) , Moulded Transition (3), Metallic conduit (4), High Level Switch (5), Main Electrical Connector (6) - External interface and Loom Assemblies (sheathed in Raychem tube) (7).. Figure 2 shows the Drop Tank Loom Assemblies of fighter and Trainer Aircraft.

Figure 3 shows Dedicated Leak Check Test Rig for Drop Tank Loom Assemblies of fighter and Trainer Aircraft. .

6. DETAILED DESCRIPTION OF THE INVENTION

A Leak test rig (Figure 3) is designed in the way of its installation inside the drop tank for carrying out leak checks of Drop Tank Looms at Looms sub assembly stage to ensure leak proof electrical looms before its final integration on Drop Tank which mainly comprises of the following: .

i) 1 inch dia and 2200 mm length pipe (13 of Figure 3) and another pipe (14 of Figure 3) of

1450mm Length

ii) Sleeve and coupling (12 of Figure 3)to assemble the loom assemblies of Refuel-cum-Stop Air Valve and Fuel Low Level Switch along with the Molded Transition^ of Figure
3) shrinked over metallic tubing in the same way as installed in the drop tank (1(a), 1(b) and 3 of Figure 2)

iii) Budd Tape(11 of Figure 3) to seal the loom assembly of Fuel High Level Switch (1(c) of Figure 2)

iv) Digital Pressure gauge (0-20PSI) to monitor the inlet pressure (10 of Figure 3).

v) Nipple (9 of Figure 3) to fix the hose for compressed air.

vi) Clamps (15 of Figure 3) for fixing the pipeline with L- angle Support (16 of Figure 3)

;er fabrication of drop tank loom assemblies on bench Leak test may be carried out with newly

signed Leak Test Rig (Figure 3) as per the following procedure.

a) Assemble the fabricated Drop Tank Loom Assemblies (1(a) & 1(b) of Figure 3) on to the

Leak Check Rig using Sleeve and coupling.

b) Secure the other end (1(c) of Figure 3) of the Loom on to the rig using Budd Tape.

c) Supply compressed air (7 of Figure 3) through Hose (8 of Figure 3) to the rig in steps of 2 PSI till 10 PSI, check the points for any Leaks using Snoop Solution. No Leak permitted at any electrical interface joints.

d) Carryout re-work in case leak is observed from any electrical interface joints.

e) After successful Leak check of Drop Tank Loom Assemblies, these loom assemblies are cleared to use in Drop Tank for installation.

The present invention facilitates 100% leak proof build of drop tank loom assemblies at subsystem level of looming stage.

The designed leak test rig is easy to use and portable. It enables quality inspection for

effective and accurate testing and it avoids the judgment of qualified product with certain

errors as unqualified