• . 

1. REASON 

PartofGE's A\"iatDn Business 

I SERVICE BULLETIN I 

SERVICE BULLETIN 

SERVICE BULLETIN D8400-61-A66 

TRANSMITIAL LETTER FOR REVISION NO. 7 

Dated Dec 01/11 

A. The requirement for the continued inspection of Hub, Actuator and Backplate Assemblies, Part No. 

697037001 , can be cancelled by the incorporation of a modified backplate and slipring assembly in 

accordance with Dowty Propellers Service Bulletin D8400-61-94. The Compliance paragraph 1. D. (1) (c) 

has been included to reflect this. 

2. ACTION 

A. Remove and destroy existing pages 1 and 2 of the service bulletin and replace with revised pages 1 and 2 

dated Dec 01/11 . 

Dowty Propellers 

Anson Business Park, Cheltenham Road East, Gloucester, GL2 9QN ENGLAND 

Telephone: 01452 716000 Facsimile: 01452 716001 
• 

For Europe, Africa, India and 

Middle East contact: 

Dowty Propellers 

Anson Business Park 

Cheltenham Road East, 

ID8WifT 

CAGE CODE: U7387 

For Asia, Australasia and the Pacific 

contact: 

Dowty Propellers 

Anson Business Park 

Cheltenham Road East, 

For the Americas 

contact: 

Dowty Propellers 

Gloucester, GL2 9QN, United Kingdom 

T: + 44 (0)1452 716000 

Gloucester, GL2 9QN, United Kingdom 

T: + 44 (0)1452 716000 

114 Powers Court 

Sterling , VA 20166 

United States of America 

T: + 1 (703) 421 4434 

F: + 44 (0)1452 716001 F: + 44 (0)1452 716001 F: + 1 (703) 450 0087 

Manual Ref: 61-10-49 

SERVICE BULLETIN ALERT 

PROPELLER - HUB, ACTUATOR AND BACKPLATE ASSEMBLY- APPLICATION OF SEALANT BETWEEN 

BUSBARS AND BACKPLATE 

1. Planning Information 

WARNING: FAILURE TO IMPLEMENT ANY INSTRUCTION GIVEN HERE, AS AMENDED FROM TIME TO 

TIME BY DOWTY PROPELLERS, MAY ENDANGER HEALTH AND SAFETY. 

A. 

B. 

Effectivity 

Aircraft affected 

Propeller Type No.: 

Unit affected 

Part No. 

Serial Nos. 

Reason 

de Havilland Dash 8 Series 400, 401 and 402 

R408/6-123-F /17 

Hub, Actuator and Backplate Assembly LRU 

697037001 

All Hub, Actuator and Backplate Assembly LRU's from Serial No. DAP0347 will 

include this service bulletin before delivery 

( 1) There have been reports of short circuits between the busbar assemblies and the backplate 

assembly. This has caused double generator failure on aircraft in flight. 

Copyright (2009), GE Aviation Systems Ltd., U.K 

The information contained in this document is GE Aviation Systems Ltd proprietary information and is disclosed in confidence. It is the 

property of GE Aviation Systems Ltd and shall not be used, disclosed to others or reproduced without the express written consent of GE 

Aviation Systems Ltd , including, but without limitation, it is not to be used in the creation , manufacture, development, or derivation of any 

repairs , modifications, spare parts, designs, or configuration changes or to obtain FAA, CAA, EASA, or any other government or 

regulatory approval to do so. If consent is given for reproduction in whole or in part, th is notice and the notice set forth on each page of 

this document shall appear in any such reproduction in whole or in part. 

All technical documentation and information contained herein , with respect to assembly and disassembly, cleaning, inspection methods 

and limits, repair methods and limits, operational limits, life limits and the like, have been developed and approved for use with this 

equipment and parts that have been manufactured and/or approved by GE and that have been maintained in accordance with GE 

technical documentation and recommendations . GE has no contractual or legal obligation for, nor knowlege of, non-GE-approved parts 

and repairs. Accordingly, this document is not intended to apply to non-GE-approved parts and repairs . 

VP4084 

Feb 9/07 

1 Dec 01/11 (Revision 7) 

D8400-61-A66 

Page 1 of 6 
I 

ltCDWifY 

SERVICE BULLETIN 

ALERT 

C. Description 

( 1) 3M 5300 or 3M 4200 sealant is to be applied between the bus bar assemblies and the backplate 

assembly. The sealant has been successfully used as a solution to the problem. 

(2) The sealant layer will add extra insulation and provide a bond between the two components. 

D. Compliance 

(1) ALERT 

(a) This service bulletin must be completed on all units within 5,000 FH from the release of this 

service bulletin. 

(b) The sealant must be re-applied at every 10,000 FH restoration in accordance with this 

service bulletin. This is applicable to all unit serial numbers. 

(c) The requirement for the continued inspection of Hub, Actuator and Backplate Assemblies, 

Part No. 697037001, can be cancelled by the incorporation of a modified backplate and 

slipring assembly in accordance with Dowty Propellers Service Bulletin D8400-61-94. 

E. Approval 

(1) This service bulletin was approved and classified as ALERT. The technical content of this service 

bulletin was approved under the authority of Design Organisation Approval No. EASA.21J.008. 

This service bulletin is the subject of EASA airworthiness directive 2009-0114. 

F. Manpower 

(1) This service bulletin will take approximately 2 hours to complete for each hub actuator and 

backplate LRU. 

NOTE : The above manhours are given for maintenance schedule functions only. The estimate 

includes the time to do the maintenance procedures in the Accomplishment Instructions 

only. It does not include the time to prepare the equipment for the maintenance 

procedures. 

G. Weight and Balance 

(1) None. 

H. References 

(1) Dowty Propellers Component Maintenance Manual61-10-49. 

I. Other Publications Affected 

(1) Dowty Propellers Component Maintenance Manual61-10-49. 

2. Material information 

A. Material 

To complete this modification make an order for Modification Set VP4084. This modification set will have 

the items that follow: 

Qty for 

Part No. Each Unit Name 

( 1) P999358 0.5 tube 3M Sealant 5300, Black 

or 

TBA 0.5 tube 3M Sealant 4200, Black 

Feb 9/07 

Dec 01/11 (Revision 7) 

GE Aviation Systems Ltd Proprietary Information Use o rdisdosure of data co ntan ed on this sheet is subject to the rest ridions on the cover or first page 

Price/Supply 

Apply to Dowty Propellers 

for the supply date of the 

Modification item 

D8400-61-A66 

Page2 
I 

SERVICE BULLETIN 

ALERT 

B. The modification will be included in new production by the manufacturer from Serial No. DAP0347. 

Pre modification spares will not be kept. Quantities are for each unit. 

New Qty for Pre S.B. Instructions 

Part No. Each Unit Name Part No. 

(1) 697037001 

(2) 697037203 

Hub, Actuator and 

Backplate Unit 

Slip Ring and 

Backplate Assembly 

697037001 

697037202 Amend part no. 

as necessary. 

Refer to para 3.C. 

C. Tooling 

(1) None. 

3. Accomplishment Instructions 

The figure/item numbers in parentheses in the text agree with those used in the illustrated parts list. Only the 

primary figure/item numbers are used. 

A. Procedure 

Feb 9/07 

(1) Off-wing - Disassembled (Refer to Figure 1) 

(a) Remove the slipring and backplate assembly (2-50) from the hub and actuator: refer to the 

Component Maintenance Manual. 

(b) Remove the self locking nuts (2-80) and the washers (2-90) which attach the busbar 

assemblies (2-140 and 2-170) to the backplate assembly (4-20). 

(c) Remove the bolts (2-100) and the washers (2-110) which attach the slipring assembly 

(2-200) to the backplate assembly (4-20). 

(d) Remove the slipring assembly (2-200) with the attached busbar assemblies (2-140 and 

2-170) from the backplate assembly (4-20). 

(e) Fully clean the busbar assemblies (2-140 and 2-170) and the backplate assembly (4-20): 

refer to the Component Maintenance Manual, CLEANING. 

(f) Refer to Figure 1. Apply a th in layer of black 3M 5300 or 3M 4200 sealant to the rear of the 

busbar assemblies (2-140) or (2-170) (the face which is adjacent to the backplate assembly 

when assembled) at the position shown and length given. 

(g) Assemble the slipring assembly (2-200) with the attached busbar assemblies (2-140 and 

2-170) to the backplate assembly (4-20): refer to the Component Maintenance Manual. 

(h) Make sure that the busbar assemblies (2-140) or (2-170) are flush against the backplate 

assembly (4-20) with the minimum thickness of sealant. The quantity of sealant must be 

enough to make a good bond between each busbar and the backplate. 

(i) Clean any unwanted sealant from the backplate assembly (4-20) and busbar assemblies 

(2-140 and 2-170). 

Allow the sealant to cure for 45 minutes. 

(k) Complete the assembly of the slipring assembly (2-200) to the backplate assembly (4-20): 

refer to the Component Maintenance Manual. 

(I) Complete the assembly of the propeller: refer to the Component Maintenance Manual. 

D8400-61-A66 

Aug 17/11 (Revision 6) Page 3 

GE Aviati on Systems Ltd Proprietary Information Use or disdosure of data contai1ed on this sheet is subject to the rest ridions on the cover or first page 
I 

lt8Wirlf 

Part ofGE's Aviation Busine-ss 

SERVICE BULLETIN 

ALERT 

B. Procedure 

(1) On-wing -Assembled (Refer to Figure 2) 

(a) Loosen the self locking nuts which attach the busbar assemblies to the backplate assembly 

(4-20) 

(b) Use a blunt tool to carefully lift the busbar assembly from the backplate. Make sure that you 

do not permanently distort the busbar assembly. 

(c) Fully clean the busbar assembly and the backplate assembly: refer to the Component 

Maintenance Manual, CLEANING. 

(d) Refer to Figure 1. Apply a thin layer of black 3M 5300 or 3M 4200 sealant to the rear of the 

busbar assembly (the face which is adjacent to the backplate assembly when assembled) at 

the position shown and length given. Refer to PS5709-21. 

(e) Remove any excess sealant with a suitable tool such as a soft spatula. 

(f) Remove the blunt tool used to lift the busbar assembly from the backplate assembly. 

(g) Press the busbar assembly against the surface of the backplate to make sure that the sealant 

makes a good bond. 

(h) Make sure that the busbar assembly is flush against the backplate assembly with the 

minimum thickness of sealant. The quantity of sealant must be enough to make a good bond 

between each busbar and the backplate. 

(i) Torque the self locking nuts which attach the busbar assemblies to the backplate assembly to 

28.5 to 31.5 lbf in (3,22 to 3,56 N m): refer toPS 51002-1. 

U) Clean any unwanted sealant from the backplate assembly and busbar assemblies. 

(k) Repeat the procedure for each busbar. 

(I) Do a check of each busbar assembly to make sure that they are not distorted. 

CAUTION : MAKE SURE THAT THE CLEARANCE BETWEEN THE BUSBAR ASSEMBLIES AND 

THE DUAL PULSE PROBE ASSEMBLY IS SATISFACTORY. REFER TO AMM TASK 

61-20-06-820-801 . 

(m) Allow the sealant to cure for a minimum of 45 minutes before returning the propeller to 

service. 

C. Make a Record 

(1) When the instructions of this service bulletin have been completed: 

-Change the part number of the slip ring and backplate assembly to 697037203 

- Write Service Bulletin D8400-61-A66 in the propeller log book. 

Feb 9/07 D8400-61-A66 

Aug 17/11 (Revision 6) Page 4 

GE Aviation Systems Ltd Proprietary Information Use or disdosure of data co ntail ed on this sheet is subject to the restridions on the cover or first page 
I 

BACKPLATE 

ASSEMBLY (4-20) 

APPLY 3M 5300 OR 3M 4200 

SEALANT TO THE REAR OF 

THE BUSBAR ASSEMBLIES 

(2-140) AND (2-170) BETWEEN 

THE BUSBAR ASSEMBLIES 

AND THE BACKPLATE ASSEMBLY 

(4-20) 

BACKPLATE ASSEMBLY 

(4-20) 

SERVICE BULLETIN 

DETAIL A 

225 mm 

(8.86 in) 

A 

ALERT 

BUSBAR 

ASSEMBLIES (2-140) 

0 8400-00283-1 

Application of 3M 5300 or 3M 4200 Sealant - Propeller Off-wing - Disassembled 

Figure 1 

Feb 9/07 D8400-61-A66 

Jun 16/10 (Revision 5) Page 5 

GE Aviation Systems Ltd Proprietary Information 

Use or disdosure of data contai"ted on this sheet is su b~ct to the re st ridions on the cover or first page 
I 

IDctWirT 

l'an <:of GE'.to Av·intion Uus.int-ss 

APPLY 3M 5300 OR 3M 4200 

SEALANT TO THE REAR OF 

THE BUSBAR ASSEMBLIES 

BETWEEN THE BUSBAR 

ASSEMBLIES AND THE 

BACKPLATE ASSEMBLY 

BACKPLATE ASSEMBLY 

SERVICE BULLETIN 

SECTION A- A 

BUSBAR 

ASSEMBLIES 

Application of 3M 5300 or 3M 4200 Sealant - Propeller On-wing - Assembled 

Figure 2 

ALERT 

225 mm 

(8.86 in) 

0 8400-00284-1 

Feb 09/07 D8400-61-A66 

Jun 16/10 (Revision 5) Page 6 

GE Aviation Systems Ltd Proprietary Information 

Use or disdosure of data contained on this sheet is su b~ct to the res1 tidions on the cover or first page