JT8D-STD SERIES ENGINE MAINTENANCE PLANNING GUIDE PN 820671PART IV: WORKSCOPE PLANNING GUIDE Orig. Date: 11/15/99 Rev. Date: 11/06/09 File Name: JT8D_STD_IV_14_MGBX SECTION 14: MAIN GEARBOX (MGBX) Reference 14.1 BUILD GROUP GENERAL EM 72-61-00 14.1.1 GENERAL a) Review JT8D-STD #1 Reliability Service Bulletins applicable to the Build Group. b) Determine level of maintenance using factors including but not limited to: • • TSLSV / CSLSV & TSLHM / CSLHM Engine removal schedule c) Maintenance levels for this module are: • Module Level Inspection For modules that are not scheduled for disassembly that are either installed or removed from the engine. • Check & Repair / Modification For modules that are partially disassembled to allow access to specific parts requiring repair or modification only without performing any performance or stability related refurbishments. • Heavy Maintenance For modules that are beyond the recommended threshold for heavy maintenance or require complete disassembly and refurbishment to restore performance and stability. This workscope sets the TSLHM / CSLHM to zero as major rotating parts are fully disassembled and NDT inspected. IV-14-1 etc. Table 2. and the Minimum Build Standard. regardless of the level of maintenance workscope being performed. General Information. However.4.3. Categories 1 through 6. but have not exceeded H/M interval. IV-14-2 . Pratt & Whitney recommends incorporation of Service Bulletins in reference to # 1 Reliability. Date: 11/06/09 File Name: JT8D_STD_IV_14_MGBX SECTION 14: MAIN GEARBOX (MGBX) Reference 14. Date: 11/15/99 Rev. operators should comply with FAA mandated AD Notes and Pratt & Whitney issued Alert Service Bulletins pertaining to the gearbox. “Gearbox Heavy Maintenance Soft Time Interval” (2): Gearboxes that have accumulated high time/cycle. Note (1): Refer to WPG Section 2.JT8D-STD SERIES ENGINE MAINTENANCE PLANNING GUIDE PN 820671 PART IV: WORKSCOPE PLANNING GUIDE Orig. Note: Depending on the level of maintenance workscope being performed and parts exposure. hardware condition.1 BUILD GROUP GENERAL EM 72-61-00 14.2 DETERMINATION OF LEVEL OF MAINTENANCE The decision tree chart that follows provides guidance for determining the level of maintenance for this group. Pratt & Whitney also recommends incorporation of Categories 7 and 8 Service Bulletins that are applicable to each gearbox based on the operator’s service and maintenance experience. Also consider factors such as: LLP. GEARBOX In-Shop Gearbox removed for extensive damage due to an engine event? NO YES TSLHM /CSLHM or TSN /CSN exceeded H/M interval recommendation (1) or scheduled H/M (2) or Removed for maintenance history YES NO Module Level Inspection results unacceptable? NO YES YES Significant oil leakage noted? Or Accumulation of chips on chip detectors or operational problems NO Heavy Maintenance Check & Repair / Modification No further action required.1. 3 FOCUS AREAS a) Bearing deterioration. Date: 11/15/99 Rev. e) Housing split line oil leakage. and internal radial clearance whenever that bearing has more than 6. Our current accessory bearing maintenance recommendations is similar and provided below. is necessary to determine if this same philosophy would be beneficial.1 BUILD GROUP GENERAL EM 72-61-00 14. the installation of new bearings • Proper disassembly. f) Mail oil filter cover leaks. bore diameter. as a basis.000-14. It discusses the following topics: • Bearing light maintenance inspection criteria • Bearing heavy maintenance inspection criteria • Re-use of old bearings vs. This change was made to agree with the other Heavy Maintenance soft time interval given in this MPG. or refurbishment. for our customers. comprehensive recommendation platform. P&W provides accessory bearing inspection criteria and allows for “source demonstration approved” accessory bearing refurbishment.JT8D-STD SERIES ENGINE MAINTENANCE PLANNING GUIDE PN 820671 PART IV: WORKSCOPE PLANNING GUIDE Orig.000 hours) to 10.000 hours since new.000-12. JT8D-Std & -200 Engine Manuals. Please note that the only change in recommendations from the SIR article is a change in the Heavy Maintenance interval (from 10. g) JT8D-ALL ACCESSORY BEARING MAINTENANCE RECOMMENDATIONS: A JT8D SIR Article provided maintenance recommendations for accessory bearings based on a field survey of customers and shops and successful implementation in the field. c) CSD gearshaft disengagement. 11 & 12) – Maintenance Practices Guidelines To Preclude Premature JT8D Oil Pump Drive Gear Bearing Failures IV-14-3 . the bearings should be inspected whenever the Main Accessory Gearbox is available (removed from the engine).1. It also states that individual customer analysis. repair.000 hours. and re-assembly procedures to extend the service life of the MGB • MOF selection & • Engine oil monitoring The intent was to provide a realistic. b) Carbon seal deterioration. and the Main Accessory Gearbox is opened (Front Cover removed). with regard to the re-use or the replacement of accessory bearings. d) Main oil pump assembly. For customers experiencing a high rate of premature failure. Date: 11/06/09 File Name: JT8D_STD_IV_14_MGBX SECTION 14: MAIN GEARBOX (MGBX) Reference 14. inspection. Inspection-01– Accessory Bearing Visual Dimensional Inspection June 2003 JT8D Service Information Report (SIR) Article (pages 10. outside diameter. 1) Bearing Check & Repair (Light Maintenance) Inspection Criteria: Inspect bearings for hardness. 72-09-52. field experience based. in addition to whenever the Front Cover is removed. and the parts of the bearing cage that touch the balls or rollers. To do the functional surfaces inspection. refurbishment. Only Level 1 (cleaning. Insp/Check-02 – Visual Inspection – Antifriction Bearing Inspection JT8D-Std & -200 Engine Manuals. raceway honing to 0. Index JT8D-Std & -200 Engine Manuals.000 – 12. bore diameter. These bearings should be inspected as described in the Standard Practices Manual (Section 70-35). no grinding is permitted) are allowed.0003” Max. INSP-01) provides serviceability inspection requirements for Accessory Bearings. Insp/Check -01 – Engine Bearings – Antifriction Bearing Inspection Standard Practices Manual. 000 hours. These requirements should be thought of as tables of “fits & clearances” and. and internal radial clearance requirements. Repair00 – Accessory Bearing Repair/Part No. Inspection-01 – Accessory Bearing Visual Dimensional Inspection JT8D-Std & -200 Engine Manuals.full serviceability inspection by a P&W approved source) at 10. 72-09-52.. 70-35-00. This interval can be used as an initial starting point and could be adjusted (up or down) depending on the customer’s experience. do not comprise the complete serviceability inspection. Within this procedure is a NOTE that directs these procedures to all “demountable” or “semi-demountable” JT8D accessory bearings. bearings must be disassembled by removing the retention-rivets and separating the two cage halves. all parts of an inner or outer race that touch the balls or rollers. The Engine Manual provides hardness. re-plating/replacement of the retainer. visual inspections. Date: 11/15/99 Rev. and dimensional inspections) and Level 2 (Level 1 plus replacement of roller elements. The Engine Manual also states that defects on the “functional surfaces” of a bearing are the most important to find. NOTE: The referenced JT8D Engine Manual (72-09-52.1 BUILD GROUP GENERAL EM 72-61-00 Standard Practices Manual. in the case of Heavy Maintenance. These “demountable” or “semi-demountable” types of bearings are defined as those on which it is possible to remove an inner or outer race (without using tools) and do an inspection of the balls or rollers. Date: 11/06/09 File Name: JT8D_STD_IV_14_MGBX SECTION 14: MAIN GEARBOX (MGBX) Reference 14. 70-35-00. and reassembly) must be done by a P&W approved source as indicated in the Engine Manual (72-09-52. This disassembly (and subsequent cleaning. REPAIR-00 & REPAIR-01).JT8D-STD SERIES ENGINE MAINTENANCE PLANNING GUIDE PN 820671 PART IV: WORKSCOPE PLANNING GUIDE Orig. 72-09-52. IV-14-4 . These “functional surfaces” of a bearing are the ball or roller surfaces. Repair01 – Recondition Accessory Drive Gearbox Bearings Repair (Vendor Application) 2) Bearing Heavy Maintenance/Overhaul Inspection Criteria: Replace or Inspect the bearing (Level 1 and Level 2 . See below for more information on the option to replace or inspect & repair. inspection. outside diameter. 72-09-52. JT8D-STD SERIES ENGINE MAINTENANCE PLANNING GUIDE PN 820671 PART IV: WORKSCOPE PLANNING GUIDE Orig. Date: 11/06/09 File Name: JT8D_STD_IV_14_MGBX SECTION 14: MAIN GEARBOX (MGBX) Reference 14. This analysis must consider both the technical merits (ability to achieve the required service life without problems) and the economics of costs associated with the complete inspection of the bearing (by a P&W approved source) and follow-on refurbishment vs.000 – 29. In some cases.000 hours or more) and that they are currently getting as much 26.000 hours without problems. used/refurbished bearings: Some customers that experienced premature bearing failures have adopted a maintenance philosophy of installing “new” bearings at heavy maintenance (overhaul) and have seen a significant improvement in service life.000 hours between overhauls. the customer has stated that new bearings installed at overhaul provide failure free service to the next scheduled Main Accessory Gearbox overhaul (16.1 BUILD GROUP GENERAL EM 72-61-00 3) Installation of new bearings vs. Date: 11/15/99 Rev. the cost of a new bearing. IV-14-5 . Individual customer analysis is necessary to determine if this same philosophy would be beneficial. they have accumulated as much as 30. In one case. compared to refurbished bearings. JT8D-STD SERIES ENGINE MAINTENANCE PLANNING GUIDE PN 820671 PART IV: WORKSCOPE PLANNING GUIDE Orig. Individual parts that are removed as a result of providing access for inspection of the build group shall receive a minimum of visual inspection. If visual inspection reveals unserviceable conditions. if inspection reveals a questionable condition that cannot be confirmed in assembled state. d) If gearbox is removed. Gearbox front to rear housing split line for evidence of oil leakage. b) Remove and inspect the two magnetic chip detectors (if used). Date: 11/06/09 File Name: JT8D_STD_IV_14_MGBX SECTION 14: MAIN GEARBOX (MGBX) Reference 14. f) Inspect CSD drive gear movement. However. inspect tower shaft mounting areas for condition.1 GENERAL a) Visually inspect the Main Accessory Gearbox Group for obvious surface defects and/or deformations. parts shall be fully inspected and repaired c) This section covers all parts that may be exposed for inspection on an assembled gearbox. b) The inspection limits and repairs referenced for build group level inspection are intended to be performed on the listed parts only when assembled as a complete build group and are not to be applied to disassembled parts.2 BUILD GROUP LEVEL INSPECTION 14.400 hour intervals. MM 72-00-00 Insp/Check-01 EM 72-00-00 Check-01 Note: It is recommended that oil strainer or filter be removed for inspection at 250 .2 INSTALLED ON ENGINE OR REMOVED a) Visually inspect: • • Accessory mounting pads and ports for evidence of oil leakage.2. It is recognized that not all of these parts may be exposed depending on the level of engine disassembly. Standard Practices Manual Standard Practices Manual EM 72-61-00 Check-01 EM 72-61-01 Inspection-01 IV-14-6 .2. which will preclude proper functioning of any of the parts. Date: 11/15/99 Rev. It is not necessary to perform additional disassembly for the sole purpose of exposing the listed parts. Remove CSD if necessary. e) Visually inspect exposed surfaces of the gearbox for general conditions. c) Visually inspect exposed accessory drive splines and gears for wear. further disassembly shall be accomplished to ensure the condition does not affect the airworthiness of the engine. 14. Parts that pass visual inspection requirements may be returned to service. f) Visual Inspect all bearing journals and bearings. c) Visually inspect all accessible areas of the gearbox for general conditions.2 GENERAL a) Cleaning of parts is not required. For conditions not described below refer to the EM individual part Visual Inspect section for damage limits. inspect gearbox mount pad and QAD ring. if removed. Date: 11/15/99 Rev. Remove CSD if necessary.3 GEARBOX ASSEMBLED OR PARTIALLY DISASSEMBLED a) Inspect gearbox main mount for pin-to-hanger and pin-to-gearbox wear and front mount for bolt-togearbox wear. Repair if necessary. Parts that fail shall receive full inspection and repair in accordance with EM requirements. Clean. d) Inspect CSD drive gear movement. or loose studs.1 DISASSEMBLY a) Disassemble the gearbox as necessary to perform specific repairs or modifications.3 CHECK & REPAIR / MODIFICATION EM 72-00-00 EM 72-61-00 Disassembly-01 14. h) In-situ visual inspection of hydraulic pump gearshaft.3. If installed. Date: 11/06/09 File Name: JT8D_STD_IV_14_MGBX SECTION 14: MAIN GEARBOX (MGBX) Reference 14. 14. Note: Reference Focus Points. EM 72-09-73 Inspection-01 EM 72-61-00 Check-01 EM 72-61-51 Inspection-01 Standard Practices Manual EM 72-61-61 EM 72-61-62 EM 72-61-63 Standard Practices Manual IV-14-7 . Item g for Bearing Maintenance Recommendations.3. g) If fuel pump is removed. and Visual Inspect oil pressure relief valve.JT8D-STD SERIES ENGINE MAINTENANCE PLANNING GUIDE PN 820671 PART IV: WORKSCOPE PLANNING GUIDE Orig. i) j) Replace all oil pump seals. tap and torque QAD ring. Inspect all exposed gears and splines for wear. pulled. c) For exposed parts treat all fits as IFR code B unless otherwise specified. rear internal spline.3. b) Visual Inspect exposed areas (not disassembled) for damage and distress that will preclude proper functioning of any of the parts. 14. b) Check for damaged. e) Disassemble. 4. b) The workscope instructions provided in this section represent P&W recommendations that encompass a broad range of conditions an engine may be subjected to.1 DISASSEMBLY a) Remove Main Accessory Gearbox (MGBX) group.2 GENERAL a) Cleaning of parts is required. b) Remove external components from main accessory gearbox assembly. Date: 11/15/99 Rev. EM 72-61-00 Cleaning-01 IV-14-8 . c) Disassemble gearbox assembly to individual parts and subassemblies. Individual operators / heavy maintenance shops may use knowledge gained through their operating experience to modify this workscope.JT8D-STD SERIES ENGINE MAINTENANCE PLANNING GUIDE PN 820671 PART IV: WORKSCOPE PLANNING GUIDE Orig. 14.4.4 HEAVY MAINTENANCE EM 72-00-00 EM 72-00-61 Removal-01 or Removal-02 EM 72-00-61 Removal-03 Removal-04 Removal-05 Removal-06 Removal-07 Removal-08 Removal-09 Removal-10 Removal-11 Removal-12 Removal-13 Removal-14 Removal-15 Removal-16 Removal-17 Removal-18 Removal-19 Removal-20 Removal-21 Removal-22 Removal-23 Removal-24 Removal-25 Removal-26 Removal-27 EM 72-61-00 Disassembly-01 14. Date: 11/06/09 File Name: JT8D_STD_IV_14_MGBX SECTION 14: MAIN GEARBOX (MGBX) Reference 14. installation for Flow Test. e) Dimensional Inspect mount lug bushings for wear. h) Oil Flow Test assembly.4.3 HOUSING ASSEMBLY. IV-14-9 . Date: 11/15/99 Rev. (Post S/B 6097) c) FPI d) Visual Inspect for general physical condition.5 STARTER DRIVE GEARSHAFT ASSEMBLY a) Visual Inspect for general physical condition.6 STARTER DRIVE SPUR GEARSHAFT (ASSEMBLY) a) Visual and Dimensional Inspect. EM 72-00-00 Inspection-01 & EM 72-61-00 Inspection-04 EM 72-09-00 EM 72-00-00 Special Procedure01 EM 72-61-01 Disassembly-01 Disassembly-03 EM 72-61-00 Inspection-01 EM 72-61-01 Inspection-01 Inspection-02 Assembly-01 Assembly-03 Assembly-04 Assembly-05 EM 72-61-02 EM 72-61-00 Inspection-01 EM 72-61-02 Inspection-01 Inspection-02 EM 72-61-10 Inspection-01 EM 72-61-11 Inspection-01 14. Date: 11/06/09 File Name: JT8D_STD_IV_14_MGBX SECTION 14: MAIN GEARBOX (MGBX) Reference 14. e) Refer to Section 19. Dimensional Inspection of IFR code B fits are required only if assembly criteria are not met unless otherwise specified. (See EM definition of IFR code B) d) Individual parts not covered in the EM shall receive a minimum of visual inspection. i) Install gearbox flange clamp body.4. GEARBOX FRONT a) FPI b) Visual Inspect for general physical condition. f) Install strainer elements into gearbox housing. 14. 14.JT8D-STD SERIES ENGINE MAINTENANCE PLANNING GUIDE PN 820671 PART IV: WORKSCOPE PLANNING GUIDE Orig. b) Remove gearbox flange clamp body.4 HEAVY MAINTENANCE c) Dimensional Inspection of part features are required for IFR code A fits.4. c) Dimensional Inspect bearing to bushing fits.4.4 HOUSING ASSEMBLY. GEARBOX REAR a) Remove strainer element assembly. (Post S/B 6097) 14. g) Oil Nozzle . clearances. Recommended Oil Systems Best Build Practices for additional recommendations pertaining to the gearbox Build Group. and limits only unless otherwise specified. EM 72-61-14 Inspection-01 14. Date: 11/06/09 File Name: JT8D_STD_IV_14_MGBX SECTION 14: MAIN GEARBOX (MGBX) Reference 14. Date: 11/15/99 Rev.7 ROTARY DEAERATOR IMPELLERS (FRONT AND REAR) a) Visual and Dimensional Inspect.4. EM 72-61-20 EM 72-61-21 Inspection-01 14. EM 72-61-22 Inspection-01 IV-14-10 .4.JT8D-STD SERIES ENGINE MAINTENANCE PLANNING GUIDE PN 820671 PART IV: WORKSCOPE PLANNING GUIDE Orig.8 STARTER DRIVE GEARSHAFT COUPLING a) Visual and Dimensional Inspect.4.9 GEARBOX DRIVE BEVEL AND SPUR GEARSHAFT ASSEMBLY a) FMPI b) Visual and Dimensional Inspect.11 ACCESSORY DRIVE BEVEL GEAR (CSD) a) FMPI b) Visual and Dimensional Inspect. EM 72-61-15 EM 72-61-16 Inspection-01 14.10 ACCESSORY AND COMPONENT DRIVE GEARSHAFT ASSEMBLY a) FMPI b) Visual and Dimensional Inspect.4.4 HEAVY MAINTENANCE EM 72-61-12 Inspection-01 14. 14.4. EM 72-61-27 Inspection-01 14.16 GEARBOX DRIVESHAFT (OUTER) COUPLING a) Visual and Dimensional Inspect.4.14 GEARBOX DRIVE SPUR GEAR a) FMPI b) Visual and Dimensional Inspect.15 HYDRAULIC PUMP DRIVE GEARSHAFT ASSEMBLY a) FMPI b) Visual and Dimensional Inspect. EM 72-61-36 Inspection-01 IV-14-11 .4 HEAVY MAINTENANCE EM 72-61-23 Inspection-01 14. Date: 11/15/99 Rev.4.JT8D-STD SERIES ENGINE MAINTENANCE PLANNING GUIDE PN 820671 PART IV: WORKSCOPE PLANNING GUIDE Orig. 14.12 GEARBOX COUPLING (CSD) a) FMPI b) Visual and Dimensional Inspect.4. EM 72-61-25 EM 72-61-26 Inspection-01 14.4. Date: 11/06/09 File Name: JT8D_STD_IV_14_MGBX SECTION 14: MAIN GEARBOX (MGBX) Reference 14.4.13 FUEL PUMP DRIVE GEARSHAFT ASSEMBLY a) FMPI b) Visual and Dimensional Inspect. EM 72-61-30 EM 72-61-31 Inspection-01 14. 19 TACHOMETER DRIVE OIL SEAL HOUSING AND SEAL a) Disassemble tachometer drive oil seal housing and seal.4. detail parts.20 MAIN OIL PUMP a) Visual inspect bearing. Date: 11/15/99 Rev. 14. b) Assemble tachometer drive oil seal housing and seal.4. EM 72-61-44 Disassembly-01 Assembly-01 EM 72-61-50 Inspection-01 Inspection-02 14.4.4 HEAVY MAINTENANCE EM 72-61-37 Inspection-01 14. gears. b) Dimensional Inspect.4.21 OIL PRESSURE RELIEF VALVE ASSEMBLY a) Visual Inspect strainer.18 TACHOMETER DRIVE (N2) GEARSHAFT ASSEMBLY a) FMPI b) Visual and Dimensional Inspect. Date: 11/06/09 File Name: JT8D_STD_IV_14_MGBX SECTION 14: MAIN GEARBOX (MGBX) Reference 14.4. housings. EM 72-61-40 EM 72-61-41 Inspection-01 14.17 GEARBOX DRIVESHAFT BEVEL GEAR a) FMPI b) Visual and Dimensional Inspect. EM 72-61-51 Inspection-01 Inspection-02 IV-14-12 . housing. seals etc. b) Dimensional Inspect.JT8D-STD SERIES ENGINE MAINTENANCE PLANNING GUIDE PN 820671 PART IV: WORKSCOPE PLANNING GUIDE Orig. 14. dimensions etc. re-lap starter drive gearshaft seal face.24 POWER LEVER CROSS SHAFTS a) Visual Inspect: • • • Bearing journals. b) Replace deoiler carbon seal with new.4.22 MAIN OIL FILTER (15 MICRON) a) Clean or replace (operator option).4.4. b) Oil Pressure Check pressure relief valve. Inspection-02 EM 72-61-59 Inspection-01 IV-14-13 . b) Backflush the strainer with clean water. The oil strainer cover for damage and warping. d) Visual Inspect: • • Reusable type strainer elements.JT8D-STD SERIES ENGINE MAINTENANCE PLANNING GUIDE PN 820671 PART IV: WORKSCOPE PLANNING GUIDE Orig. etc.4. 14. Fluorocarbon bearings for wear.25 ACCESSORY DRIVE FACE TYPE OIL SEALS a) Visual Inspect for nicks. Date: 11/06/09 File Name: JT8D_STD_IV_14_MGBX SECTION 14: MAIN GEARBOX (MGBX) Reference 14. c) Measure spring compression. Internal / external spline wear. cracks. EM 72-61-58 Inspection-01 b) Dimensional Inspect bearing and spline wear. 14.23 MAIN OIL STRAINER OPTION (40 MICRON) a) Clean the strainer and its parts. EM72-61-55 Cleaning-01 Inspection-01 Inspection-02 14. Date: 11/15/99 Rev.4 HEAVY MAINTENANCE EM 72-61-54 Inspection-01 14. JT8D-STD SERIES ENGINE MAINTENANCE PLANNING GUIDE PN 820671 PART IV: WORKSCOPE PLANNING GUIDE Orig. b) Dimensional Inspect.4.4. b) Apply antigalling compound to threads. EM-72-61-63 Inspection-01 IV-14-14 .4. Date: 11/15/99 Rev. b) Dimensional Inspect.4 HEAVY MAINTENANCE EM 72-09-52 Standard Practices Manual Inspection-01 14. EM 72-61-61 EM 72-61-62 Inspection-01 Front Coupling Rear Coupling 14. c) Inspect all functional surfaces. Date: 11/06/09 File Name: JT8D_STD_IV_14_MGBX SECTION 14: MAIN GEARBOX (MGBX) Reference 14.28 FUEL PUMP COUPLING (QUICK DISCONNECT). Repair-01 14. Item g for Bearing Maintenance Recommendations.26 ACCESSORY BEARINGS a) Visual Inspect for general physical condition. See SIR June 2003 Maintenance Practices Guidelines EM 72-61-60 Inspection-01 14. Note: Reference Focus Points.27 FUEL CONTROL LINKAGE a) Visual Inspect: • Links and link bearings for wear or damage.4. FRONT AND REAR a) Visual Inspect for wear or damage.29 GEARBOX QUICK DISCONNECT NUT a) Dimensional Inspect threads for wear. Cushion bonding.4.4.4.34 GEARBOX HOUSING GASKET a) Visual Inspect for: • • Aluminum base for surface corrosion or damage. EM 72-61-66 Inspection-01 14. EM 72-61-68 Inspection-01 14. scores.30 OIL TANK a) Visual Inspect: • • For dents. Oil outlet tube support bracket weld.32 OIL TANK STRAP ASSEMBLY a) Visual Inspect for: • • General physical condition. or damage. Rubber section for cuts. 14.JT8D-STD SERIES ENGINE MAINTENANCE PLANNING GUIDE PN 820671 PART IV: WORKSCOPE PLANNING GUIDE Orig. Date: 11/15/99 Rev. Gage (if installed) for readability of markings.4 HEAVY MAINTENANCE EM 72-61-65 Inspection-01 14. etc. missing.31 OIL TANK CAP ASSEMBLY a) Visual Inspect: • • For broken.33 ACCESSORY DRIVE OIL SEAL HOUSINGS a) Dimensional Inspect face wear. Date: 11/06/09 File Name: JT8D_STD_IV_14_MGBX SECTION 14: MAIN GEARBOX (MGBX) Reference 14. and damaged parts.4. distortion.4. EM 72-61-69 Inspection-01 IV-14-15 . EM 72-61-67 Inspection-01 14. 37 GEARBOX GROUP ASSEMBLY a) Perform Leak Test of assembled gearbox.36 GEARBOX MOUNTING BOLTS a) Visual Inspect for general physical condition. Date: 11/15/99 Rev.4 HEAVY MAINTENANCE EM 72-61-80 Inspection-01 14. Date: 11/06/09 File Name: JT8D_STD_IV_14_MGBX SECTION 14: MAIN GEARBOX (MGBX) Reference 14. EM 72-61-81 Inspection-01 Repair-01 14.JT8D-STD SERIES ENGINE MAINTENANCE PLANNING GUIDE PN 820671 PART IV: WORKSCOPE PLANNING GUIDE Orig. 14. b) Replace antigalling compound.4.35 GEARBOX MOUNTING PINS a) Visual Inspect for hardface wear into parent material.4.4. EM 72-61-00 Assembly-01 IV-14-16 .