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Copyright (2017) General Electric Company, U.S.A.
1.PLANNING INFORMATION
A.Effectivity
* * * FOR GEnx-1B64, -1B64/P1, -1B64/P2, -1B67, -1B67/P1, -1B67/P2, -1B70, -1B70/75/P1, -1B70/75/P2, -1B70/P1, -1B70/P2, -1B70C/P1, -1B70C/P2, -1B74/75/P1, -1B74/75/P2, -1B76A/P2
This Service Bulletin is applicable to all GEnx-1B engines.
This Service Bulletin has been introduced in production to these GEnx-1B engines:
•
GEnx-1B engines, serial numbers 956-936 and up.
The seal housings P/N 1682M90P16 and P/N 2406M07P01 are affected by this Service Bulletin.
B.Description
This Service Bulletin provides instructions to inspect the affected seal housings for damage applying RTV silicone elastomer to the concerned areas.
C.Compliance
Category 3
GE recommends that you do this service bulletin at the next shop visit of the engine/module.
Impact C
This recommendation is to address a condition that may result in a Non-Event operational disruption, Unscheduled Engine Removals (UER), Out-Station-Removals or Aircraft on the Ground (AOG).
NOTE:
This Service Bulletin can be accomplished on wing or 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 reliability.
(2)Condition:
During a general visual inspection, the seal housings have been found loose or with partial/complete fracture, resulting in maintenance burden.
(3)Cause:
The air duct seal P/N 1682M91P08 has been found to be the root cause of this failure, due to a shrinkage condition caused by the temperature that exceeds the air duct seal material capability.
(4)Inspection:
This Service Bulletin defines a visual inspection to the seal housings installed in the high pressure turbine (HPT) air manifolds (eight locations) applying RTV silicone elastomer in all the interface areas.
(5)Substantiation:
Substantiation is by fleet experience.
F.Approval
This Service Bulletin contains no modification information that revises the approved configuration and therefore does not require FAA or regulatory approval.
G.Manpower
After you get access to the seal housings, you will need approximately 2.0 man-hours for each engine or component.
In case any seal housing is damaged, the time for replacement will increase.
H.Weight and Balance
Weight and balance are not changed.
I.References (Use the latest version of these documents)
GEnx-1B, Boeing 787 Aircraft Maintenance Manual (AMM)
GEK 9250, Commercial Engine Standard Practices Manual (SPM)
GEK 112851, GEnx-1B Engine Manual (EM)
GEK 112864, GEnx-1B Engine Illustrated Parts Catalog (EIPC)
NOTE:
The reference documents listed below are for the engine manufacturer's internal use only:
CID: 575911
BPP/EPEX No.: 16-72-00-61569, 16-72-00-61571
J.Publications Affected
None.
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
 
2406M07P01*
(8)
Housing, Seal
4,557.00
(1)
5
 
1682M91P08*
(16)
Seal, Air Duct
145.25
(1)
5
*The required quantity to perform this Service Bulletin will depend on the condition found during the inspection. The mentioned quantities of eight seal housings and 16 air duct seals are the total of seal housings and air duct seals installed per engine.
NOTE:
Prices are provided for planning purposes and are subject to change.
(3)Consumables:
 
Code Number
Description
 
C01-007
RTV, Silicone Elastomer
 
C04-002
Solvent, General (solvent)
 
C04-035
Solvent, General (isopropyl alcohol)
B.Industry Support Information
None.
C.Configuration Chart
None.
D.Parts Disposition
None.
E.Tooling - Price and Availability
None.
3.ACCOMPLISHMENT INSTRUCTIONS
A.General
(1)If the engine is on wing, prepare the aircraft for the seal housings (1, Figure 1) inspection as follows:
(a)To safely open the left and right thrust reversers on the applicable engine, do as follows:
1Do the leading edge slat retraction (task selection) operation. Refer to the GEnx-1B, Boeing 787 AMM, TASK 27-81-00-27B-110A-A.
2Do the leading edge slat system deactivation. Refer to the GEnx-1B, Boeing 787 AMM, TASK 27-81-00-24A-510B-A.
3Do the deactivation of the thrust reverser for ground maintenance. Refer to the GEnx-1B, Boeing 787 AMM, TASK G78-31-00-15H-510B-A.
4Open the fan cowl panels. Refer to the GEnx-1B, Boeing 787 AMM, TASK G71-11-04-00B-540A-A.
5Open the thrust reversers. Refer to the GEnx-1B, Boeing 787 AMM, TASK G78-31-00-00-15B-540A-A.
(2)Do an inspection of the seal housings (1, Figure 1) at eight locations as follows:
(a)Do an inspection for cracks as follows:
1If you find cracks, replace the seal housing (1) as specified in steps 3.A.(3) and 3.A.(5).
2If you do not find cracks, the seal housing (1) is serviceable. Continue with step 3.A.(6).
(b)Do an inspection for nicks and scratches as follows:
1Any amount, with a maximum of 0.005 inch (0.13 mm) in depth, is permitted.
2If nicks and scratches are not within the limits, replace the seal housing (1) as specified in steps 3.A.(3) and 3.A.(5).
3If you do not find nicks/scratches, the seal housing (1) is serviceable. Continue with step 3.A.(6).
(c)Do an inspection for dents as follows:
1Any amount with a smooth contour is permitted if the seal housing (1) can be correctly assembled.
2If dents do not agree with the condition in step 3.A.(2)(c)1
, replace the seal housing (1) as specified in steps 3.A.(3) and 3.A.(5).
3If you do not find dents, the seal housing (1) is serviceable. Continue with step 3.A.(6).
(3)Remove the damaged seal housing (1) and remove and discard the air duct seal (2). Refer to the GEnx-1B EM, 72-00-02, DISASSEMBLY 003.
(4)Do an inspection for nicks, scratches, or cracks in the duct end areas of the HPT air manifolds as follows:
(a)Any amount is permitted as long as the nicks, scratches, or cracks do not go fully through the material thickness. The HPT air manifold is serviceable, continue with step 3.A.(6).
NOTE:
Figure 2 shows HPT air manifold damage examples.
(b)If the damage is out of the permitted limits, the HPT air manifold is not serviceable. Replace the HPT air manifold. For disassembly instructions, refer to the GEnx-1B EM, 72-00-02, DISASSEMBLY 003, Subtask 72-00-02-030-441 and, for assembly instructions, refer to the GEnx-1B EM, 72-00-02, ASSEMBLY 004, CONFIG 01, Subtask 72-00-02-440-119 or Subtask 72-00-02-440-276.
NOTE:
Figure 2 shows HPT air manifold damage examples.
(5)Install the new seal housing (1, Figure 1) and the air duct seals (2). Refer to the GEnx-1B EM, 72-00-02, ASSEMBLY 004, CONFIG 01 or CONFIG 02.
WARNING:
REFER TO THE PRODUCT LABEL AND THE MANUFACTURERS (MATERIAL) SAFETY DATA SHEET (SDS) FOR INSTRUCTIONS ON THE HAZARDS, STORAGE, SAFE HANDLING AND PROPER USE OF CONSUMABLE PRODUCTS.
(6)Apply C01-007 RTV silicone elastomer in all eight seal housings (1, Figure 1) as follows:
(a)Clean the surface with C04-002 solvent or C04-035 isopropyl alcohol.
(b)Apply C01-007 RTV silicone elastomer to the interface between the seal housing (1) and HPT air manifold to prevent further movement of the seal housing (1). Make sure only to apply on the area of interest and not on the surrounding hardware. Refer to Figure 1.
NOTE:
It is recommended to let the C01-007 RTV silicone elastomer cure for 8 to 12 hours.
(7)If the engine is on wing, put the aircraft back to its usual condition as follows:
(a)To safely close the left and right thrust reversers on the applicable engine, do as follows:
1Close the left and right thrust reversers. Refer to the GEnx-1B, Boeing 787 AMM, TASK G78-31-00-15B-740A-A.
2Close the left and right fan cowl panels. Refer to the GEnx-1B, Boeing 787 AMM, TASK G71-11-04-00B-740A-A.
3Do the thrust reverser (after ground maintenance) activation. Refer to the GEnx-1B, Boeing 787 AMM, TASK AG78-31-00-15G-730B-A.
4Do the leading edge slat system activation. Refer to the GEnx-1B, Boeing 787 AMM, TASK 27-81-00-24A-730B-A.
Seal Housing Location and RTV Silicone Elastomer Application
Figure 1   (Sheet 1)
Seal Housing Location and RTV Silicone Elastomer Application
Figure 1   (Sheet 2)
HPT Air Manifold Damage Examples
Figure 2