DOC AIRBUS | AMM A320FVisual Inspection of the Transfer Gearbox (TGB) Assembly without Special Equipment [CFML]
TASK 72-62-00-210-803-A
Visual Inspection of the Transfer Gearbox (TGB) Assembly without Special Equipment
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Work Zones and Access Panels
C. Referenced Information
3. Job Set-up
Subtask 72-62-00-941-060-A
Subtask 72-62-00-210-054-A
Subtask 72-62-00-410-066-A
[Rev.10 from 2021]
2026.04.01 02:54:35 UTC
Visual Inspection of the Transfer Gearbox (TGB) Assembly without Special Equipment
WARNING:
BE CAREFUL WHEN YOU DO WORK ON THE ENGINE PARTS AFTER THE ENGINE SHUTDOWN. USE APPLICABLE THERMAL GLOVES. THE ENGINE PARTS CAN STAY HOT FOR ONE HOUR AFTER SHUTDOWN AND CAN BURN YOU.
ZONE: 400
1. Reason for the JobSelf explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | 1 | ACCESS PLATFORM 1M(3 FT) |
| No specific | 1 | BORESCOPE DIA 4 MM (0.16 IN)-FLEXIBLE, FRONT/SIDE VIEW |
| No specific | 1 | CALIPER |
| No specific | AR | WARNING NOTICE(S) |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 400 | POWER PLANT, NACELLES AND PYLONS |
| FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1) | |
| 437AL, 438AR | |
| FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2) | |
| 447AL, 448AR | |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 71-13-00-010-803-A | Opening of the Fan Cowl Doors |
| TASK 71-13-00-410-803-A | Closing of the Fan Cowl Doors |
| TASK 72-62-00-000-802-A | Removal of the Transfer Gearbox Assembly |
| TASK 72-62-00-100-801-A | Cleaning of the Transfer Gearbox (TGB) Assembly |
| TASK 72-62-00-400-802-A | Installation of the Transfer Gearbox Assembly |
Transfer Gearbox (TGB) AssemblySubtask 72-62-00-941-060-A
A. Safety Precautions
(1) On the center pedestal, on ENG panel 115VU:
(a) Make sure that the ENG/MODE selector switch is in the NORM position.
(b) Make sure that the ENG/MASTER 1(2) control switch was in the OFF position not less than five minutes before you do this procedure.
(c) Put a WARNING NOTICE(S) in position to tell persons not to operate:
(a) Make sure that the ON legend of the FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) in position to tell persons not to energize FADEC 1(2).
Subtask 72-62-00-010-067-A (1) On the center pedestal, on ENG panel 115VU:
(a) Make sure that the ENG/MODE selector switch is in the NORM position.
(b) Make sure that the ENG/MASTER 1(2) control switch was in the OFF position not less than five minutes before you do this procedure.
(c) Put a WARNING NOTICE(S) in position to tell persons not to operate:
- The ENG/MODE selector switch
- The ENG/MASTER 1(2) control switch.
(a) Make sure that the ON legend of the FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) in position to tell persons not to energize FADEC 1(2).
B. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR.
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR.
(2) Put an ACCESS PLATFORM 1M(3 FT) in position.
4. Procedure(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR.
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR.
(2) Put an ACCESS PLATFORM 1M(3 FT) in position.
Subtask 72-62-00-210-054-A
A. Visual Inspection of the Transfer Gearbox (TGB) Assembly
(1) Make sure that the TGB assembly (1) to be examined is clean (Ref. AMM TASK 72-62-00-100-801).
(2) The following visual inspections can be performed only if the TGB assembly is removed (Ref. AMM TASK 72-62-00-000-802) and (Ref. AMM TASK 72-62-00-400-802):
Subtask 72-62-00-210-055-A (1) Make sure that the TGB assembly (1) to be examined is clean (Ref. AMM TASK 72-62-00-100-801).
(2) The following visual inspections can be performed only if the TGB assembly is removed (Ref. AMM TASK 72-62-00-000-802) and (Ref. AMM TASK 72-62-00-400-802):
- Support Bearing (10)
- Splines of the bevel gear (2)
- Oil level ring (13)
| Examine | Maximum Serviceable Limits | Remarks |
|---|---|---|
| 1.Examine all the areas of the TGB assembly (1) that are seen for: | | |
| A.Cracks | Not serviceable | |
| B.Missing surface protection for non machined surfaces | Five percent of visible checked surface | |
| C.Missing surface protection for all others areas | Not serviceable | |
| D.Corrosion | Not serviceable | |
| 2.Examine the area K, J, and G of the TGB assembly for: | | |
| A.Scratches, nicks and dents, see the sheet 2 of the figure: | Not serviceable | See repair (Ref. AMM D/O 72-62-00-35). |
| 3.Examine the areas of the inserts 0.2500-28 UNJF-3B (5), see the sheet 2 of the figure: | | |
| A.Wear of internal threads | Any amount, if the total cumulated length is less than 1/2 one full thread | |
| B.Looseness | Any amount, if the two keys are correctly in place | |
| C.Missing insert or key | Not serviceable | |
| D.Self-locking quality (running torque) | Acceptable, if running torque is between 3.54 lbf.in (0.04 m.daN) and 30.004 lbf.in (0.34 m.daN). | |
| 4.Examine all areas of the nipples (3), see the sheet 1 and 2 of the figure: | | |
| A.Wear of threads | Any amount if effective threads are not less than one after chasing. | |
| B.Circumferential scratches on areas A and C | Any amount, not more than 0.0051 in. (0.13 mm) in depth after the removal of high metal. Refer to LEAP-00-70-41-11-01A-655B-D | |
| C.Circumferential scratches on area B, see the sheet 4 of the figure: | Any amount if not felt with 0.04 in. (1.02 mm) radius scriber | |
| D.Axial scratches on areas A and C, see the sheet 4 of the figure: | Any amount, not more than 0.0051 in. (0.13 mm) depth after the removal of high metal. Refer to LEAP-00-70-41-11-01A-655B-D. | |
| E.Axial scratches on area B, see the sheet 4 of the figure: | Not serviceable | |
| F.Nicks on area A, see the sheet 4 of the figure: | Any amount, maximum of 0.031 in. (0.79 mm) in depth after removal of high metal. Refer to LEAP-00-70-41-11-01A-655B-D. | |
| G.Nicks on areas C and B, see the sheet 4 of the figure: | Not serviceable | |
| H.Scratches, nicks and dents on seal grooves | Not serviceable | |
| J.Scratches, nicks and dents on hexagon (location 1), see the sheet 4 of the figure: | Any amount, if the hexagon can be maintained by the wrench tool. | |
| K.Deformation and wear on safety wire holes | Serviceable, if metal around hole is not cracked or torn. | |
| L.Tear-out of safety wire holes | Serviceable, if one hole remains. | |
| 5.Examine the location 2 of the bearing support assembly (10) that are seen for: see the sheet 1 of the figure: and see the sheet 3 of the figure: | | |
| A.Scratches, nicks, dents and scores | Not serviceable | See repair (Ref. AMM D/O 72-62-00-35). |
| 6.Examine all areas of the tapped extraction holes of the bearing support (10), that are seen for: see the sheet 3 of the figure: | | |
| A.Wear of threads | Not serviceable if less than 1/2 entrance thread. Refer to LEAP-00-70-41-11-01A-655B-D | |
| 7.Examine the inserts of the bearing support (10), for: see the sheet 3 of the figure: | | |
| A.Wear of internal threads | One full thread cumulative or continuous may be missing after removal of worn provided not less than one-half lead-in thread remains. | |
| B.Looseness | Not serviceable | |
| C.Missing insert or keys | Not serviceable | |
| 8.Examine the outer diameter of the bearing support (10), for: see the sheet 3 of the figure: | | |
| A.Fretting, galling, or wear on end surfaces | Any amount not exceeding 25% of the surface acceptable if outer diameter is between 3.9374 in. (100.01 mm) and 3.9389 in. (100.05 mm) | |
| 9.Examine seal grooves of transfer tube assembly (11), see the sheet 3 of the figure: | | |
| A.Scratches, nicks, dents and scores | Not serviceable | |
| 10.Examine sealing surfaces of transfer tube assembly (11), that are seen for: see the sheet 3 of the figure: | | |
| A.Scratches, nicks, dents and scores | Not serviceable | |
| 11.Examine all other areas of transfer tube assembly (11), that are seen for: see the sheet 3 of the figure: | | |
| A.Scratches, nicks, dents and scores | Any amount that cannot be felt with a 0.02 in. (0.51 mm) radius scriber. | See repair (Ref. AMM D/O 72-62-00-35). |
| 12.Examine tapped extraction holes of transfer tube assembly (11), that are seen for: see the sheet 3 of the figure: | | |
| A.Worn threads | Any amount if less than 1/2 entrance thread after removal of high metal. Refer to LEAP-00-70-41-11-01A-655B-D. | |
| 13.Examine inserts of transfer tube assembly (11), that are seen for: see the sheet 3 of the figure: | | |
| A.Wear of internal threads | One full thread cumulative or continuous may be missing after removal of worn provided not less than one-half lead-in thread remains | |
| B.Looseness | Not serviceable | |
| C.Missing insert and keys | Not serviceable | |
| 14.Examine all areas of the safety wires, that are seen for: | | |
| A.Broken | Not serviceable | |
| B.Missing | Not serviceable | |
| 15.Examine all areas of the nozzles (7), that are seen for: see the sheet 2 of the figure: | | |
| A.Worn surface treatment | Not serviceable | |
| B.Scratches, nicks and scores | Not serviceable | |
| 16.Examine plug of the nozzles (7), that are seen for: see the sheet 2 of the figure: | | |
| A.Loose | Not serviceable | |
| B.Missing plug | Not serviceable | |
| 17.Examine clamping surfaces of the nozzles (7), that are seen for: | | |
| A.Print (clamping surface) | Acceptable if not felt with 0.030 in. (0.76 mm) radius scriber | |
| 18.Examine the orifice of the nozzles (7), that are seen for: see the sheet 3 of the figure: | | |
| A.Blocked | Not serviceable | |
| B.Worn with changes or decreases flow | Not serviceable | |
| C.Fouling of orifice | Not serviceable | |
| 19.Examine the seal groove (9), that are seen for: see the sheet 3 of the figure: | | |
| A.Scratches, nicks, dents and scores | Not serviceable | |
| 20.Examine all other areas of the slider (4), that are seen for: see the sheet 3 of the figure: | | |
| A.Scratches, nicks, dents, scores | Not serviceable | See repair (Ref. AMM D/O 72-62-00-35). |
| 21.Examine slider flange of the slider (4), that are seen for: see the sheet 4 of the figure: | | |
| A.Fretting or wear | Any amount, up to 0.004 in. (0.10 mm) in depth | |
| 22.Examine all areas of the seal ball joint seal (8), figure, that are seen for: see the sheet 3 of the figure: | | |
| A.Cut | Not serviceable | |
| B.Scratches, nicks and dents | Not serviceable | |
| 23.Examine the areas of the gear shaft tail, that are seen for: | | |
| A.Dents, nicks and scratches | Not serviceable | |
| 24.Examine all areas of the splines (2), that are seen for: see the sheet 1 of the figure: | | |
| A.Scratches | Any amount, if not felt with 0.0300 in. (0.76 mm) radius scriber | |
| B.Nicks, dents and burrs | Any amount, up to 0.0252 in. (0.64 mm) in maximum depth | |
| C.Wear | Refer to paragraph 4.B. | |
| 25.Examine all areas of the fire shield blanket that are seen for: | | |
| A.Dented or crushed areas | Not serviceable | |
| B.Cuts, tears, and holes in outer skin | Not serviceable | |
| C.Looseness of installed blankets | Not serviceable | |
| D.Oil soaking (internal) | Not serviceable | |
| E.Loose bond of protection strip of stitches | Not serviceable | |
| 26.Examine all areas of the retainer sector that are seen for: | | |
| A.Fretting on all areas (other than seating faces) | Not serviceable | |
| B.Fretting on seating faces | Acceptable if not felt with 0.0300 in. (0.76 mm) radius scriber | |
| 27.Examine all areas of the identification plate (6), that are seen for: see the sheet 2 of the figure: | | |
| A.Looseness or loss of serrated nails | Not serviceable | |
| 28.Examine the Area H of the TGB housing (12), that are seen for: see the sheet 2 of the figure: | | |
| A.Scratches, nicks and dents | Any amount that cannot be felt with a 0.03 in. (0.76 mm) radius scriber. | See repair (Ref. AMM D/O 72-62-00-35) |
| 29.Examine all sealing surfaces of the TGB housing (12), that are seen for: see the sheet 2 of the figure: | | |
| A.Scratches, nicks and dents | Not serviceable | |
| B.Fretting | Not serviceable | |
| POST SB 72-0337 | | |
| 30.Examine all areas (chamfers, inner diameter) of the oil level ring (13) | | If the oil level ring (13) is removed from the bevel gear it must be replaced by a new one. |
| A.Nicks, dents, scratches which no not cross corners | Not serviceable | |
| B.Cracks, missing material | Not serviceable | |
| C.Axial, radial scratches which cross corners | Not serviceable | |
| D.Deformation (before removal) | Not serviceable | |
| E.Corrosion | Not serviceable | |
| Not serviceable | | |
| | | |
| A.Wear, fretting | Any amount that cannot be felt with a 0.03 in. (0.76 mm) radius scriber | |
| | | |
| A.Wear, fretting | Any amount that cannot be felt with a 0.03 in. (0.76 mm) radius scriber | |
| END OF POST SB 72-0337 | | |
B. Inspect the gear shaft splines of TGB bevel gear (2) with a 0.03 in. (0.76 mm) radius scriber.
(1) If no wear is felt with the radius scriber:
(a) The TGB bevel gear (2) splines are serviceable.
(2) If the wear is felt with the radius scriber, calculate the depth D1 of the wear using the following procedure:
(a) Use a micrometer screw gauge or a CALIPER between 7 spline teeth of the TGB bevel gear (2).
1 Measure M1 distance over 7 spline teeth on the area without wear, close to the groove.
2 Measure M2 distance over 7 spline teeth between one third and the middle of the area with wear, from the groove side.
3 Calculate the depth on the wear: D1 = M1 - M2.
4 Repeat the instructions given from Step 4.B.(2)(a)1 to Step 4.B.(2)(a)3 on 4 teeth at 90 degrees from each other (tooth no. 1, 10, 20, 30).
5 Report in Table 1 the maximum wear depth D1 measured.
(b) Do the following procedure according to the maximum wear depth found in Table 1: refer to Table 2.
Table 1: Measurements form for the gear shaft splines of the TGB bevel gear (2)
Table 2: Replacement scenario
Subtask 72-62-00-210-059-A (1) If no wear is felt with the radius scriber:
(a) The TGB bevel gear (2) splines are serviceable.
(2) If the wear is felt with the radius scriber, calculate the depth D1 of the wear using the following procedure:
(a) Use a micrometer screw gauge or a CALIPER between 7 spline teeth of the TGB bevel gear (2).
1 Measure M1 distance over 7 spline teeth on the area without wear, close to the groove.
2 Measure M2 distance over 7 spline teeth between one third and the middle of the area with wear, from the groove side.
3 Calculate the depth on the wear: D1 = M1 - M2.
4 Repeat the instructions given from Step 4.B.(2)(a)1 to Step 4.B.(2)(a)3 on 4 teeth at 90 degrees from each other (tooth no. 1, 10, 20, 30).
5 Report in Table 1 the maximum wear depth D1 measured.
(b) Do the following procedure according to the maximum wear depth found in Table 1: refer to Table 2.
Table 1: Measurements form for the gear shaft splines of the TGB bevel gear (2)
| | M1 (mm) Area without wear | M2 (mm) Area with wear | D1=M1-M2 (mm) Wear depth |
|---|---|---|---|
| Tooth no. 1 | | | |
| Tooth no. 10 | | | |
| Tooth no. 20 | | | |
| Tooth no. 30 | | | |
| | | Maximum wear depth= | Report maximum value |
Table 2: Replacement scenario
| Scenario | Maximum wear depth is: | Replacement of current TGB and RDS required |
|---|---|---|
| 1 | < 0.0031 in. (0.08 mm) | In 300 Engine Flight Hours (EFH) |
| 2 | >= 0.0031 in. (0.08 mm) and < 0.0066 in. (0.17 mm) | In 50 Engine Flight Hours (EFH) |
| 3 | >= 0.0066 in. (0.17 mm) and < 0.0082 in. (0.21 mm) | In 2 Engine Cycles (ECY) |
| 4 | >= 0.0082 in. (0.21 mm) | Without delay. |
C. Inspect the oil level ring (13) on the TGB installed on wing according to the following procedure:
POST SB 72-0337
(1) Insert the BORESCOPE DIA 4 MM (0.16 IN)-FLEXIBLE, FRONT/SIDE VIEW through sleeve assembly (14).
(2) Go up bypassing the TGB bevel gear (2) to reach the level of the bearing support window (16).
(3) Pass through the bearing support window (16).
(4) Go up towards the shaft and put the borescope between the outer radial shaft (15) and the TGB bevel gear (2).
(5) Perform a 360° inspection of the oil level ring (13) to make sure it is not deteriorated and is correctly installed in the groove of the TGB bevel gear (2).
END POST SB 72-0337
5. Close-upPOST SB 72-0337
(1) Insert the BORESCOPE DIA 4 MM (0.16 IN)-FLEXIBLE, FRONT/SIDE VIEW through sleeve assembly (14).
(2) Go up bypassing the TGB bevel gear (2) to reach the level of the bearing support window (16).
(3) Pass through the bearing support window (16).
(4) Go up towards the shaft and put the borescope between the outer radial shaft (15) and the TGB bevel gear (2).
(5) Perform a 360° inspection of the oil level ring (13) to make sure it is not deteriorated and is correctly installed in the groove of the TGB bevel gear (2).
NOTE: Alternative solution is to keep fixed the borescope and turn the TGB using accessory gearbox hand crank.
(6) In case of abnormal conditions to the oil level ring (13), please contact CFM.END POST SB 72-0337
Subtask 72-62-00-410-066-A
A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR.
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR.
(3) Remove the access platform(s).
(4) Remove the WARNING NOTICE(S).
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR.
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR.
(3) Remove the access platform(s).
(4) Remove the WARNING NOTICE(S).