1. Title of the invention
Under Carriage Bush Extraction and Proof testing tool to confirm the adhesive strength of re-bonded bush on deep Penetrating fighter Aircraft
2. Field of invention
This invention is related to the Design, Manufacturing, Test Procedure and quality assurance for Under Carriage Bush Extraction and Proof testing tool for deep Penetrating fighter Aircraft. The Tool is designed and fabricated and new Proof testing procedure is introduced for Under Carriage Bush Extraction and Proof testing procedure for re-bonding of bushes on deep Penetrating fighter Aircraft.
3. Use of invention
This invention is used on hinge attachment of Under Carriage follow-up door for re-bonding of loosened bushes by method of extraction and undertaking Proof test on the rebounded bushes to ensure the adhesive strength of the re-bonded bushes on the hinge attachment of the under Carriage follow-up door and thereby recording and documenting for reference during every induction of deep Penetrating fighter Aircraft for Major Servicing.
4. Prior art
This method is unique. There was no previous tool to confirm the bonding strength of the bushes after re-bonding with suitable adhesives. And hence thereby introduced new procedure for re-bonding and confirming the adhesive strength of the re-bonded bushes with a methodology of proof test on the re-bonded bushes of hinge attachment of under Carriage follow up door bush on deep penetrating fighter aircraft.
5. Draw backs of prior art
Not applicable, as this is a new Tool and Proof testing procedure developed for the first time.

6. Comparison between prior art and present invention
Not applicable, as this is a new Tool and Proof testing procedure developed for the first time.
7. Aim of the invention
Aim of the invention was to design and develop an effective and efficient tool to confirm the extraction methodology and adhesive strength of the re-bonded bushes with a new procedure for proof test on the re-bonded bushes of hinge attachment of under Carriage follow up door bush on deep penetrating fighter aircraft.
8. Summary of the present invention
This invention is used for Under Carriage follow-up door Bush Extraction and Proof testing of re-bonded bushes on hinge attachment of Under Carriage follow-up door on deep Penetrating fighter Aircraft.
The bushes and bearings in the deep Penetrating fighter Aircraft are generally bonded in there housing by a system of resin based adhesives. This method of attachment was chosen in order to avoid, as for as possible stress corrosion problems which might arise from an interference fit. The bonding procedure deforms neither the bushes, bearings or bearing cages and permits the minimum drag figures to be achieved. It also permits replacement of bushes without the need for redressing of the housing usually necessary with other form of retention; there is no limit to the number of times any item may be replaced by the bonding procedure. The components to which the bushes are bonded have been designed to with stand limited axial loads only; the axial load must not produce shear stress greater than 50 bar at ultimate load.
Due to the frequent opening and closing of the under carriage follow up doors during under carriage operating testing and flight there were chances of bushes coming out of housing in the event of failure of adhesive bonding, which is potential flight safety hazard.
The Original equipment manufacturer has not specified any test procedure and particular tool for checking the bonding strength of the bushes with housing. There

was no particular tool was available for the extraction of the bushes from housing for the replacement of bushes.
The newly invented tool serves for both bush extraction and proof testing on the re-bonded bushes to confirm the adhesive strength by application of defined torque value in the form of axial load on the aircraft.
9. Brief description of drawings
FIG.l Detail drawing of newly developed tool.
FIG.2 Illustrates the area of inert of the newly developed tool on the bush housing of under carriage follow-up door.
FIG.3 Illustrates Proof test carried out on an Aircraft.
FIG. 4 Illustrates the Adhesive Strength tested on ground with newly fabricated tool.
FIG. 5 Represents the newly fabricated tool.
10. Statement of invention
Introduction of new procedure for re-bonding of bushes in the system during Major servicing and repair of the under carriage hinge attachment bracket of Follow-up door for both extraction and re-bonding of bushes to confirm the adhesive strength of the re-bonded bushes by application of axial load on deep penetrating fighter aircraft.

11. Detailed description of invention
10.1 The newly invented tool consists of the following sub-assembly parts as per drawing and manufactured accordingly:-
The following procedure is introduced and recorded for quality analysis and certification on the re-bonding of Bushes to confirm the adhesive the adhesive strength of the bushes at the bushes coming out of housing in the event of adhesive failure. The following is followed for replacement/repair of the housing when there is a rotational play of the bushes within the housing.

10.2 Methodology for Extraction of rotating bush in the Housinq:-
a) Carryout pre-survey on the under carriage follow-up door hinge attachment area to confirm the play/free rotating of bushes in the housing and identify the bushes to be removed and record accordingly.
b) Clean the area of bushes with suitable cleaning agent to be free from dust, grease and other particles.
c) Insert the newly developed tool on the area of interest for bush extraction (Ref. Figure No.3) and apply the required torque to ensure the removal of bushes without damaging the housing of the hinge attachment of Follow-up door fitment.
10.3 Methodology for Proof testing of re-bonded bushes on hinge attachment of Follow-up
door:-
i) Remove the old adhesive from the housing without damaging the housing. Clean the
area of bonding thoroughly on base plate hinge attachment of Follow-up door holding at the area of Follow-up door holding bracket assembly. Mask the area around the hinge as required.
ii) Measure the Internal dimension of the bush housing using Digital Micrometer or
Digital Vernier. Deviations if any be recorded and accordingly new bushes has to be fabricated by maintaining a clearance fit of 0.037 mm to 0.066 mm (for diameter between 10 mm to 18 mm)
iii) Position the mating bolt at the hinge attachment to ensure the co-linearity & concentricity of the bushes at the area of installation in the housing. Bond the bushes using Araldite 2014 as per Aircraft repair manual.
iv) After fitment of the bushes minimum curing time of 72 hours be allowed and clean thoroughly the excess adhesive and ensure not spread the adhesive in the surrounding area.

v) After the curing of the bonding, remove the mandrel and subject each assembly of
hinge attachment to a test load axially to 40 lbs
vi) The components which cannot be removed from the aircraft, the load may be applied by using the extractor tool (O/DLE/T-039) used to draw the bushes al ong with necessary tools such as spanner and torque wrench. During the process, it should be ensured that the extractor threads are serviceable and that the screw rotates freely.

Claims We claim
1. Design and fabrication of Under Carriage Bush Extraction and Proof testing tool used for Under Carriage Bush Extraction and Proof testing to confirm the adhesive strength of re-bonded bush on deep Penetrating fighter Aircraft.
2. Selection of Material and Sub assembly parts used in the design and Manufacturing of tool.
3. Test Procedure adopted for Proof testing to confirm the adhesive strength of re-bonded bush on deep Penetrating fighter Aircraft.
4. The said Methodology for Extraction of rotating bush in the Housing of under Carriage Bush on deep Penetrating fighter Aircraft.
5. All sequence of operation, permutations and combinations of operations of Sub assembly parts used in the tool.