 | GEnx-1B SERVICE BULLETIN - 72-0123 R00 | Revised: 01/23/2013 |
| SB 72-0123 R00 ENGINE - Fan Stator Module, Lower Bifurcation, and Related Parts (72-00-00) - Introduction of New Support Strap and Machine Bolts | Issued: 01/23/2013 | |
| GEnx-1B SERVICE BULLETIN - 72-0123 R00 | Revised: 01/23/2013 |
| SB 72-0123 R00 ENGINE - Fan Stator Module, Lower Bifurcation, and Related Parts (72-00-00) - Introduction of New Support Strap and Machine Bolts | Issued: 01/23/2013 | |
| 1. | PLANNING INFORMATION |
| A. | Effectivity |
|
| This Service Bulletin is applicable to all GEnx-1B engines. |
| This Service Bulletin has been introduced in production to these GEnx-1B engines: |
| • |
|
| The support strap P/N 2475M75P01 and machine bolt P/N MS9556-16 are affected by this Service Bulletin. |
| B. | Description |
| This Service Bulletin provides instructions to install the new support strap P/N 2498M04P01 over the blanket and releases new machine bolts P/N MS9556-14 to attach the support strap. |
| C. | Compliance |
| Category 7 |
| GE recommends that you do this Service Bulletin at customer's convenience/option. |
| NOTE: |
|
| D. | Concurrent Requirements |
| None. |
| E. | Reason |
| (1) | Objective: |
| To introduce new parts and to improve maintainability. |
| (2) | Condition: |
| The current support strap P/N 2475M75P01 is installed around the sides and bottom of the insulation blanket in the lower bifi area. The insulation blanket wraps around the electrical harnesses. When the electrical harnesses are out of position, the mating insulation blanket envelope will be increased and the insulation strap that fits around the insulation blanket can be overly stressed. |
| (3) | Cause: |
| The current support strap P/N 2475M75P01 has 2 plies of material and the material edge distance from the grommet to the outside edge has minimum amount of material. During support strap installation, the current design can permit the grommet to liberate from the strap body. |
| (4) | Improvement: |
| The support strap grommet is modified to utilize a larger integral washer surface around the outside diameter of the grommet. |
| (5) | Substantiation: |
| Substantiation is by analysis and comparative analysis. |
| F. | Approval |
| This Service Bulletin has been reviewed by the FAA and the repair(s) and modification(s) herein comply with the applicable Federal Aviation Regulations and are FAA APPROVED for installation in the model(s) listed in this Service Bulletin. |
| G. | Manpower |
| No additional man-hours are required to comply with this Service Bulletin. |
| H. | Weight and Balance |
| Weight and balance are not changed. |
| I. | References (Use the latest version of these documents) |
| GEK 112851, GEnx-1B Engine Manual (EM) |
| GEK 112864, GEnx-1B Engine Illustrated Parts Catalog (EIPC) |
| NOTE: |
|
| J. | Publications Affected |
| GEK 112851, GEnx-1B Engine Manual (EM) |
| GEK 112864, GEnx-1B Engine Illustrated Parts Catalog (EIPC) |
| K. | Interchangeability |
| Two-way interchangeability. |
| L. | Software Accomplishment Summary |
| Not applicable. |
| 2. | MATERIAL INFORMATION |
| A. | Material - Price and Availability |
| (1) | Parts necessary to do this Service Bulletin: |
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| NOTE: |
|
| (2) | Other Spare Parts: |
| None. |
| (3) | Consumables: |
|
| B. | Industry Support Information |
| None. |
| C. | Configuration Chart |
|
| Operation Codes RE=Replace RM=Remains |
| Change Code 2=Two-way interchangeable. |
| Support Codes A=Old parts will no longer be supplied. E=Old parts will be supplied, and can be used at other engine locations. |
| D. | Parts Disposition |
| Use serviceable old parts for engines that have not changed. |
| E. | Tooling - Price and Availability |
| None. |
| 3. | ACCOMPLISHMENT INSTRUCTIONS |
| A. | General |
| (1) | Remove the two machine bolts (25-025, 72-00-00) (1, Figure 1) that attach the blanket (25-620) and the support strap (25-257) to the lower bifurcation firewall. Discard the machine bolts (25-025). |
| (2) | Remove the two machine bolts (25-254) that attach the thermal blanket (25-630) and the support strap (25-257) to support brackets (25-270 and 25-300). Discard the machine bolts (25-254). |
| (3) | Remove the support strap (25-257). |
| (4) | Remove the electrical harnesses inside the blanket (25-620) from the spring clips of the support brackets (25-270 and 25-300), the left side cable shield (01-040, 72-00-03), and the right side cable shift (01-050). |
| (5) | Pull the electrical harness slack up into the engine core area above the lower bifurcation assembly (25-010, 72-00-00) to make better clearance at the 6:00 o'clock position in the blanket area. |
| (6) | Install the electrical harnesses back into the spring clips of the support brackets (25-270 and 25-300), the left side cable shield (01-040, 72-00-03), and the right side cable shift (01-050). |
| (7) | Put the new support strap (2, Figure 1) around the blanket (25-620, 72-00-00). |
| (8) | Align the boltholes of the support strap (2) with the bolt hole grommets of the lower bifurcation firewall (01-180, 72-00-03) and the holes of the support brackets (25-270 and 25-300, 72-00-00). |
| WARNING: |
|
| (9) | If necessary, use (C02-058) lubricant or (C02-023) engine oil before the installation of the threaded fasteners. |
| (10) | Install the two new machine bolts (1) through the support strap holes and the bolthole grommets of the lower bifurcation firewall (01-180, 72-00-03) finger-tight only. |
| (11) | Install the two machine bolts (25-254, 72-00-00) through the support strap holes into the support brackets (25-270 and 25-300) finger-tight only. |
| (12) | Torque the new machine bolts (1) to 32-38 lb in. (3.6-4.3 N.m). |
| (13) | Torque the machine bolts (25-254) to 32-38 lb in. (3.6-4.3 N.m). |
