1.PLANNING INFORMATION
A.Effectivity
* * * FOR GEnx-1B54, -1B58, -1B64, -1B67, -1B70
This Service Bulletin is applicable to these GEnx-1B engines:
•
GEnx-1B engines, serial numbers 956-102 through 956-150.
This Service Bulletin has been introduced in production to these GEnx-1B engines:
•
GEnx-1B engines, serial numbers 956-151 and up.
These serial numbers are the best available data.
The hexagon shear bolt P/N J817P036A installed in the No. 15 bolt hole of the high pressure compressor (HPC) stator assembly split-line flange (No. 15 bolt), located on the 3:00 o'clock position aft looking forward (ALF) and attaching self-locking nut P/N J628P07 are affected by this Service Bulletin.
B.Description
This Service Bulletin provides a procedure to reverse the orientation of the No. 15 bolt.
C.Compliance
Category 3
GE recommends that you do this Service Bulletin at the next shop visit of the engine or module when the accessory gearbox assembly is removed from the engine.
NOTE:
This Service Bulletin can be accomplished in shop.
This Service Bulletin is offered to improve the reliability or performance of your GE product, or to help prevent the occurrence of the event or condition described in this Service Bulletin. If the operator elects not to participate in the bulletin, that decision will be taken into consideration by GE in evaluating future product performance issues that may arise in the operators fleet.
D.Concurrent Requirements
None.
E.Reason
(1)Objective:
To improve maintainability.
(2)Condition:
The 3:00 o'clock position (ALF) of the lower variable stator vane (VSV) actuation ring has the potential to contact the bottom of the No. 15 bolt.
(3)Cause:
Original stack analysis of the stage 4 VSV system hardware did not show that contact could occur between the actuation ring and No. 15 bolt.
(4)Improvement:
The No. 15 bolt is now assembled head down to prevent any contact with the end of the stage 4 VSV actuation ring.
(5)Substantiation:
Substantiation is by 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
After you get access to the HPC module, you will need approximately 2 man-hours for each engine.
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 112862, GEnx-1B Cleaning, Inspection, and Repair Manual (CIR)
GEK 112864, GEnx-1B Engine Illustrated Parts Catalog (EIPC)
NOTE:
The reference document listed below is for the engine manufacturer's internal use only:
 
CID: 573303
J.Publications Affected
GEK 112851, GEnx-1B Engine Manual (EM)
K.Interchangeability
Not applicable.
L.Software Accomplishment Summary
Not applicable.
2.MATERIAL INFORMATION
A.Material - Price and Availability
(1)Parts necessary to do this Service Bulletin:
None.
(2)Other Spare Parts:
 
Part Number
Qty/ Eng
Part Name
Unit ($) Price
Pkg Qty
Lead Time Days
 
J628P07
(1)
Nut, Self-locking
Quote
(-)
Quote
 
J817P036A
(1)
Bolt, Hexagon Shear
Quote
(-)
Quote
NOTE:
Prices are provided for planning purposes and are subject to change.
(3)Consumables:
 
Code Number
Description
 
C02-058
Compound, Thread Lubricating (GE Spec. A50TF201 Class A)
(thread lubricant)
 
C10-143
Safety Cable Assembly
(safety cable)
B.Industry Support Information
None.
C.Configuration Chart
Not applicable.
D.Parts Disposition
None.
E.Tooling - Price and Availability
None.
3.ACCOMPLISHMENT INSTRUCTIONS
A.General
(1)Before you do this Service Bulletin do the task that follows to allow access to the affected parts:
(a)Remove the main body heat shield P/N 2343M77G02. Refer to the GEnx-1B EM, 72-00-02, DISASSEMBLY 003.
B.Reorientation Procedure
(1)Disconnect the turnbuckle body (3, Figure 1) from the 3:00 o'clock position (ALF) of the HPC stator assembly as follows:
(a)Remove the self-locking nut (1) from the bolt (2) on the stage 4 bridge (4) and the turnbuckle body (3).
(b)Remove the bolt (2) from the stage 4 bridge (4) and the turnbuckle body (3).
(c)Remove the turnbuckle body (3) from the stage 4 bridge (4) clevis and make sure it is clear of the splitline flange location. Secure the turnbuckle body from the work area as required.
(2)Remove the stage 4 bridge from the stage 4 actuating rings on the 3:00 o'clock position (ALF) of the HPC stator assembly as follows:
(a)Remove the safety cable (C10-143) from the bolts.
(b)Remove the bolts from the stage 4 bridge.
(c)Remove the pins from the stage 4 bridge.
(d)Remove the stage 4 bridge from the stage 4 actuating rings.
(e)Inspect the stage 4 bridge per GEnx-1B CIR, 72-00-00, INSPECTION 001.
(3)Adjust the lever arms, stage 4 upper compressor stator actuating ring (stage 4 upper actuating ring), and stage 4 lower compressor stator actuating ring (stage 4 lower actuating ring), to allow access to the affected No. 15 bolt and self-locking nut.
NOTE:
You can use the VSV torque shaft linkage P/N 2360M57G02 to slide the stage 4 actuating rings up and down to make the space needed for the removal and installation process of the No. 15 bolt without the disassembly of other hardware.
(4)Remove the self-locking nut and bolt from the No. 15 bolt hole on the 3:00 o'clock position (ALF) of the HPC stator assembly splitline flange. Refer to Figure 2.
NOTE:
The bolt holes along the splitline flange are numbered 1 through 17. Bolt hole No. 1 is the most forward and bolt hole No. 17 is the most aft.
(5)Inspect the bolt and self-locking nut. Refer to the GEnx-1B CIR, 72-00-00, INSPECTION 001. Discard if necessary.
(6)Apply a thin layer of thread lubricant (C02-058) to the thread and surface faces of the new or removed bolt and self-locking nut.
(7)Install the new or removed bolt and self-locking nut upside down in the No. 15 bolt hole. Refer to Figure 3, Figure 4, and do as follows:
(a)Install the No. 15 bolt from the down to up side of the split flange.
(b)Hand tighten the self-locking nut until it is seated on the face of the split flange.
(c)Torque the self-locking nut to 552-648 lb in (62.4-73.2 Nm).
(8)Install the stage 4 bridge (1, Figure 5) on the stage 4 upper actuating ring (3) and stage 4 lower actuating ring (4). Refer to Figure 5 and do as follows:
(a)Make sure that the lever pin bushings (bushings) are installed correctly in the stage 4 bridge (1).
(b)Make sure that the "AFT" mark on the stage 4 bridge (1) points aft.
(c)Find the four stage 4 lever arms that are between the stage 4 actuating rings that will insert directly into the stage 4 bridge. Refer to Figure 6.
(d)Align the four stage 4 lever arms and alignment pins to match the holes in the stage 4 bridge. Refer to Figure 6.
(e)Install the stage 4 bridge on the four lever arms and alignment pins on the stage 4 actuating rings. Refer to Figure 6.
(f)Install two alignment pins (2, Figure 5) in the two holes on the stage 4 upper actuating ring (3) and stage 4 lower actuating ring (4).
(g)Attach the stage 4 bridge (1) to the stage 4 upper actuating ring (3) and stage 4 lower actuating ring (4) with six bolts (5). Tighten the bolts (5) hand-tight.
(h)Torque the six bolts (5) on the stage 4 bridge (1) to 235-275 lb in. (26.6-31.1 Nm).
(i)Safety the bolts with safety cable (C10-143).
(9)Install the turnbuckle body into the stage 4 bridge on the 3:00 o'clock position (ALF) of the HPC stator assembly. Attach the turnbuckle body with an aft-facing bolt and self-locking nut.
(a)Torque the self-locking nut to 460-540 lb in. (52.0-61.0 Nm).
C.Assembly
(1)Install the main body heat shield P/N 2343M77G02. Refer to the GEnx-1B, 72-00-02, ASSEMBLY 004.
Removal of the Turnbuckle Body from the Stage 4 Bridge
Figure 1  
Removal of the Bolt from the No. 15 Bolt Hole on the 3 Oclock Position (ALF) of the Forward HPC Case Split Flange
Figure 2  
Reversed Installation of the Bolt in the No. 15 Bolt Hole on the 3 Oclock Position (ALF) of the Forward HPC Case Split Flange
Figure 3  
Bolt No. 15 After Re-installation
Figure 4  
Installation of the Stage 4 Bridge on the Stage 4 Upper and Lower Actuating Rings
Figure 5  
Installation of the Bridges Over Lever Arms and Alignment Pins at the Forward HPC Splitline Flange
Figure 6