76 lines
28 KiB
Plaintext
76 lines
28 KiB
Plaintext
Use this procedure to do a visual inspection of the flow path surface of the fan blade polyurethane-coat.
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For visual examination of the polyurethane-coated area of the fan-blade root, refer to TASK 72-11-03-210-801-A.
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For more information about fan blade examination, refer to TASK 72-11-03-220-803-A.
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For more information about the fan rotor assembly, refer to 72-11-00-00
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SUBTASK 72-11-03-220-056-A
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A. Inspection of the Fan Blade Polyurethane Coat (Flow Path only)
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For the inspection limits, refer to Table 1: Visual Inspection of the Fan Blade for Erosion:
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==NOTE==:
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The flow path surface is the part of the blade that you can see when the blade is installed in the engine.
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==NOTE==:
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Area D extends 0.5 in. (12.7 mm) from the top of the platform along the blade and 0.5 in. (12.7 mm) from the side of the blade along the platform.
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==NOTE==:
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The polyurethane coat is black, the primer is green and the base metal is silver or gray in color.
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(a) If the missing coat areas do not show the base metal, you can extend the cycle limits by ten more cycles.
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(b) Repair the blades that you removed from service because of the missing coat and put them back in service.
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![[PW_Coating_01.jpeg]]
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![[PW_Coating_02.jpeg]]
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![[PW_Coating_03.jpeg]]
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| EXAMINE | DAMAGE | DISPOSITION |
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| --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
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| The polyurethane coat of the fan blade (1): | | |
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| All areas for: | | |
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| Missing polyurethane coat without the primer or the base metal shown | Any quantity. | Permitted for local FOD. For erosion Ref. AMM TASK 72-11-03-210-802. |
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| Missing polyurethane coat with the primer or the base metal shown | The primer or the base metal you can see less than 1.00 in.2 (645.16 mm2). | See the specified area shown in this procedure. |
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| | More than 1.00 in.2 (645.16 mm2) of the primer or the base metal that you can see for each side of the fan blade. | Not permitted. Repair or replace the blade in 750 cycles. The repaired coat must not be more than a total of 10.0 in. (254.00 mm) of the radial height on the full blade set, all quantities axially. See additional requirements for Areas D, E, X and Y. |
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| | More than 9.00 in.2 (5806.44 mm2) of the primer or the base metal that you can see for each side of the fan blade. The limits for Areas A thru E above stay applicable. | Not permitted. Repair or replace the blade in 50 cycles. The repaired coat must not be more than a total of 10.0 in. (254.00 mm) of the radial height on the full blade set, all quantities axially. See additional requirements for Area D. |
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| | Polyurethane coat that is lifted or has loss of bond. | Not permitted. In ten cycles, cut away the coat that is lifted or has loss of bond by the requirements specified in Para. 4.A.(2) Ref. AMM TASK 72-11-03-320-804. Examine the primer or the base metal that you can see to the limits specified above. |
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| ==NOTE==: <br>For the repair procedures of the fan blade polyurethane coat, refer to Para. 4.B. | | |
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| Nodules in the coat area (a nodule is a small, rounded, raised lump of coat material that can occur during the manufacturing process) | Nodules in coat must be smooth, continuous and not move with light pressure. | Permitted. |
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| Scuff marks or streaks in the coat area (scuff marks and streaks are superficial marks caused by the coated surfaces that rub against each other) | All quantities that do not show primer or base metal. | Permitted. |
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| Blend areas on the coat (can occur during the manufacturing process and can have a matte gray finish) | All quantities that do not show primer or base metal. | Permitted. |
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| Coat nicks, pits and scratches | All quantities that do not show primer or base metal. | Permitted. |
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| Area A | All the primer or the base metal that you can see, 1.00 in.2 (645.16 mm2) or less. | Not permitted. Repair or replace the blade in 2600 cycles. See "Area A adjacent to the blade tip". For areas more than 1.00 in.2 (645.16 mm2), see the "All Areas" section. |
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| Area A adjacent to the blade tip | All the primer or the base metal that you can see is not more than 0.0078 in.2 (5.03 mm2) for each side of the blade that is immediately adjacent to the blade tip. The total area does not include the plasma spray tip treatment surface area. It is not necessary for the edges of the plasma coat on the fan blade tip to have polyurethane coat. | Permitted. If the damage is not in the limits, repair or replace the blade in 2600 cycles. |
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| Area B | All the primer or the base metal that you can see, 1.00 in.2 (645.16 mm2) or less. | Not permitted. Repair or replace the blade in 1100 cycles. For areas more than 1.00 in.2 (645.16 mm2), see the "All Areas" section. |
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| Area C | All the primer or the base metal that you can see, 1.00 in.2 (645.16 mm2) or less. | Not permitted. Repair or replace the blade in 1100 cycles. For areas more than 1.00 in.2 (645.16 mm2), see the "All Areas" section. |
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| Area D | All the primer or the base metal that you can see. | Not permitted. If the galvanic isolation is not done or it is not checked, repair or replace the blade in five cycles. If the galvanic isolation is done, repair the blade in 35 cycles. Do a check for the galvanic isolation Ref. AMM TASK 72-11-03-210-803. |
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| Area E | All the primer or the base metal that you can see, 1.00 in.2 (645.16 mm2) or less. | Not permitted. If the galvanic isolation is not done or it is not checked, repair or replace the blade in 50 cycles. If the galvanic isolation is done, repair the blade in 1100 cycles. Do a check for the galvanic isolation Ref. AMM TASK 72-11-03-210-803. For areas more than 1.00 in.2 (645.16 mm2) and with the galvanic isolation, see the "All Areas" section. |
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| Area E adjacent to the blade tip | All the primer or the base metal that you can see is not more than 0.0031 in.2 (2.00 mm2) for each side of the blade that is immediately adjacent to the blade tip. The total area does not include the plasma spray tip treatment surface area. | Permitted. If not in limits and if the galvanic isolation is not done or it is not checked, repair or replace the blade in 50 cycles. If the galvanic isolation is done, repair the blade in 1100 cycles. Do a check for the galvanic isolation Ref. AMM TASK 72-11-03-210-803. |
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| Area E adjacent to the Leading Edge (LE) sheath | Gaps between the polyurethane coat and the LE sheath not more than 0.010 in. (0.254 mm) in width and is not more than the length of the LE sheath. Erosion coat must be firmly attached with no visible primer or base metal. | Permitted. If not in limits and if the galvanic isolation is not done or it is not checked, repair or replace the blade in 50 cycles. If the galvanic isolation is done, repair the blade in 1100 cycles. Do a check for the galvanic isolation Ref. AMM TASK 72-11-03-210-803. |
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| Area X of the platform, 2.0 in. (50.8 mm) or less from the ground tab | All the primer or the base metal that you can see. | Not permitted. If the galvanic isolation is not done or it is not checked, repair or replace the blade in 50 cycles. If the galvanic isolation is done, repair the blade in 1100 cycles. Do a check for the galvanic isolation Ref. AMM TASK 72-11-03-210-803. |
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| Area Y airfoil area at the Trailing Edge (TE) tip | All the primer or the base metal that you can see. | Permitted. In ten cycles, cut away the coat that is lifted or has loss of bond by the requirements specified in Para. 4.A.(2) Ref. AMM TASK 72-11-03-320-804. |
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| Area Z | Coating cracks or gaps. | Not permitted. Remove the blade from service immediately. |
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| Gaps or cracks in coating may be a sign of disbond on the fan blade cover. Refer Para. 4.E. for details Ref. AMM TASK 72-11-03-220-802. | | |
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| Area Z cover transition area for bubbled coating (air bubble under polyurethane coating). Completely or partially in the cover transition area. An air bubble can have burst showing an area of coating disbond | One bubble total of 0.500 in. (12.700 mm) maximum length parallel to the cover edge. | Not permitted. Remove the blade from service in ten cycles. Every two cycle inspect the blade for signs of disbond as specified in Para. 4.E. Ref. AMM TASK 72-11-03-220-802. Make sure there is no growth of the bubble currently identified or any additional bubbles on the cover perimeter. If the blade is found with any of the above damage, remove the blade from service immediately. |
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| | More than one bubble or any bubble beyond 0.500 in. (12.700 mm) length parallel to the cover edge. | Not permitted. Remove the blade from service immediately. |
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Table - Table 1: Visual Inspection of the Fan Blade for Erosion
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SUBTASK 72-11-03-320-053-A
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B. Repair the polyurethane coat of the fan blade (1) as follows:
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(1) Damage to the polyurethane coat that does not go through the coat and does not show the primer or the base metal is permitted. No repair is necessary Ref. AMM TASK 72-11-03-210-802.
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(2) If the damage shows the primer but does not show the base metal, do an erosion coat touch-up repair of the fan blade assembly with the coating, polyurethane, erosion resistant (Material Ref. P05-154) Ref. AMM TASK 72-11-03-320-804.
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(3) If the damage shows the primer or the base metal, do an erosion coat touch-up repair of the fan blade assembly with the epoxy (Material Ref. P05-492) Ref. AMM TASK 72-11-03-320-805.
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(4) For the fan blades that must be removed and replaced in Table 1 [Ref. AMM TASK 72-11-03-000-801](https://airnavx.lht.ham.dlh.de/airnavx/document/699554_SGML_C/toc?itemId=699554_SGML_C_EN72110300080100&itemType=DATAMODULE&wc=FSN:109;actype:A318;actype:A319;actype:A320;actype:A321;customization:DLH;doctype:AMM;tailNumber:N8383) and Ref. AMM TASK 72-11-03-400-801.
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