• 

1. REASON 

Part of GE ·s AYiat i:>n BtlSincss 

I SERVICE BULLETIN I 

SERVICE BULLETIN 

SERVICE BULLETIN 08400-61-94 

TRANSMITTAL LETTER FOR REVISION N0.3 

Dated Oct 23/12 

A. Changes made to the procedure and a new figure included. 

2. ACTION 

A. Remove and destroy existing pages 1, 2, 3, 4, 5, 6 and 9 of the service bulletin and replace with revised 

pages 1, 2, 3, 4, 5, 6, 9 and 10 dated Oct 23/12. 

Dowty Propellers 

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

Telephone: 01452 716000 Facsimile: 01452 716001 
I 

• Part ofGE's A vial ion Business 

For Europe, Africa, India and 

Middle East contact: 

Dowty Propellers 

Anson Business Park 

Cheltenham Road East, 

Gloucester, GL2 9QN, United Kingdom 

T: + 44 (0)1452 716000 

F: + 44 (0)1452 716001 

Manual Ref: 61-10-49 

CAGE CODE: U7387 

For Asia, Australasia and the Pacific 

contact: 

Dowty Propellers 

Anson Business Park 

Cheltenham Road East, 

Gloucester, GL2 9QN, United Kingdom 

T: + 44 (0) 1452 716000 

F: + 44 (0)1452 716001 

GEK 118214 

For the Americas 

contact: 

Dowty Propellers 

114 Powers Court 

Sterling, VA 20166 

United States of America 

T: + 1 (703) 421 4434 

F: + 1 (703) 450 0087 

SERVICE BULLETIN 

PROPELLER - HUB, ACTUATOR AND BACKPLATE ASSEMBLY - REPLACEMENT OF BUS BAR 

ASSEMBLIES WITH SLIP RING DE-ICER HARNESSES 

1. Planning Information 

A. Effectivity 

Aircraft affected 

Propeller Type 

Unit affected 

Part No. 

Serial Nos. 

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. DAP0927 will 

include this service bulletin before delivery. All other Serial Numbers are affected by 

this Service Bulletin. 

B. Concurrent requirements 

(1) None. 

C. Reason 

(1) There have been a small number of instances where busbar assemblies have come into contact 

with the backplate. This can result in arcing damage to the busbar(s) and, when the de-icing power 

is selected to 'on', can cause the aircraft A. C. generators to shut down. 

(2) Service bulletin 08400-61-A66 was introduced to add sealant between the busbar assemblies and 

the backplate. This was designed to hold the busbars better and to improve the insulation. 

Although this has been successful, it is not considered to be the final solution to the problem. 

Copyright (201 0). 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, this 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. 

VP4158 

Jun 14/10 

Oct 23/12 (Revision 3) 

08400-61-94 

Page 1 of 10 
Pan of GE1

s A\'iation Business 

SERVICE BULLETIN 

D. Description 

(1) The busbar assemblies are removed and replaced with slip ring de-icer harnesses. Refer to 

Figure 1. The ends of the slip ring de-icer harnesses are attached to the electrical terminals on the 

rear of the slip ring. The slip ring de-icer harnesses then go through grommets in the backplate and 

attach to the same terminal assemblies to which the blade de-icer wire harnesses attach to, on the 

front of the backplate. These terminal assemblies are also replaced with new terminal assemblies. 

Tie wraps are used to attach the slip ring de-icer harnesses to miniature tie wrap mounts installed 

on the backplate. 

(2) A Controlled Service Introduction (CSI) was completed on four backplates and slip rings which 

were modified to the instructions of the CSI service bulletin and installed to four aircraft for a 1000 

F/H test. 

E. Compliance 

1 (1) Recommended - incorporate this service bulletin at next shop visit. 

(2) Incorporation of this service bulletin is the terminating action for any Airworthiness Directive 

associated with Service Bulletin D8400-61-A66. 

F. Approval 

(1) The technical content of this service bulletin was approved by Dowty Propellers under the authority 

of Design Organisation Approval No. EASA.21 J.008. 

(2) The technical content of thi s service bulletin has been reviewed and accepted by Bombardier 

Aerospace. 

G. Manpower 

(1) This service bulletin will take approximately 3 hours to complete. 

H. Weight and Balance 

(1) None. 

I. Electrical Load Data 

(1) None. 

J. Software Accomplishment Summary 

(1) None. 

K. References 

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

(2) Dowty Propellers Standard Practices Manual 60-00-00. 

L. Other Publications Affected 

(1) Dowty Propellers Component Maintenance Manual 61-10-49. 

(2) Dowty Propellers Propeller Maintenance Manual Part 2, Chapter 61-1 0-46. 

(3) Bombardier Aerospace 0400 Aircraft Maintenance Manual. 

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GE Aviation Systems Ltd Proprietary Information Use or disdosure of data oo ntail ed on this sheet i s subject to the rest ridions on the cover or first page 
I 

Pan of GE"s Avialion Business: 

SERVICE BULLETIN 

M. Interchangeability or lntermixability of Parts 

(1) Pre and Post SB D8400-61-94 propellers are interchangeable. 

2. Materiallnformation 

A. Material-Price and Availability 

( 1) The items necessary to accomplish this Service Bulletin are given in para 2. B. 

(2) Contact your Dowty Propellers Account Manager for price and availability of parts. 

(3) . This Service Bulletin will be implemented at no charge during the next major inspection of the hub, 

actuator and backplate assembly LRU provided it is returned to a Dowty Repair facility. 

(4) Operators may contact the Dowty Propellers Account Manager to arrange a program of managed 

returns on a chargeable basis. 

B. Material Necessary 

The items necessary to accomplish this Service Bulletin are: 

Qty for 

Part No. Each Unit Name 

(1) 697037226 6 Slip ring De-icer Harness 

(2) 697037225 12 Terminal Assembly 

(3) MS20604S3W5 24 Rivet 

(3) P901519 6 Grommet 

(4) P901546 18 Miniature Tie Wrap Mount 

(5) MS3367-4 18 Tie Wrap 

(6) P999358 3M Sealant, 5300 Black 

(7) P999439 Adhesive, Loctite, 

Grade 380E 

C. Reidentified Parts 

(1) Reidentify the Slip ring and Backplate Assembly 697037221 with the new part number 697037223. 

(2) Reidentify the Backplate Assembly 697071231 with the new part number 697037222. 

(3) Reidentify the Backplate 666000457 with the new part number 666000626. 

D. Tooling 

(1) Grommet and Tie Wrap Mount Template, Part No. DAPT69-0047-00. 

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GE Aviation Systems Ltd Proprietary Information Use ordisdosure of data oontaned on this sheet is subject to the restridions on the cover or first page 
I 

I 

I 

Part of GE's Aviation Business 

SERVICE BULLETIN 

3. Accomplishment Instructions 

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

Component Maintenance Manual. Only the primary figure/item numbers are used. The process specifications 

(PS) are in the Dowty Propellers Standard Practices Manual. 

A. Procedure 

(1) 

(2) 

(3) 

(4) 

(5) 

(6) 

(7) 

(8) 

(9) 

(1 0) 

(11) 

(12) 

(13) 

Jun 14/10 

Remove the propeller from the aircraft. Refer to AMM Task 61-10-00-000-801. 

Remove the slip ring and backplate assembly (2-50) from the hub and actuator. Refer to the 

Component Maintenance Manual, DISASSEMBLY. 

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). 

Remove the slip ring assembly (2-200) from the backplate assembly (4-20). Refer to the 

Component Maintenance Manual, DISASSEMBLY. 

Remove the bolts (2-120) and the washers (2-130) and remove the busbar assemblies (2-140 and 

2-170) from the slip ring assembly (2-200). Discard the busbar assemblies (2-140 and 2-170). 

Remove the ring tongue terminals of the de-icer wire harnesses (3-80), from the terminal 

assemblies (4-40). 

Carefully remove the rivets (4-30) and remove the terminal assemblies (4-40) from the backplate. 

Discard the rivets (4-30) and terminal assemblies (4-40). 

Install the new terminal assemblies Part No. 697037225 and attach them to the backplate with new 

rivets (4-30). Refer to the Component Maintenance Manual. 

Refer to Figure 2. Use a 15 mm (0.590 in) drill or hole cutter and make six holes in the backplate at 

the positions shown. A s an al ternative, if av ailable, use the Grommet and Tie Wrap Mount 

Template, Part No. DAPT69-0047-00 to get the hole positions. 

Locally clean the backplate as necessary to remove all unwanted material. Refer to the Component 

Maintenance Manual, CLEANING. 

Apply Acetone or Exxon Actrel2221 to a lint fee cloth and fully clean the backplate. 

Apply a layer of 3M 5300 sealant around the inside diameter of the grommet holes in the backplate 

to fully seal the foam filler. Refer to PS5709-21. 

Refer to Figure 4. Install the six grommets Part No. P901519 into the holes. 

08400-61-94 

Oct 23/12 (Revision 3) Page4 

GE Aviation Systems ltd Proprietary Information Use o rdisdosure of data oo ntai1 ed on this sheet is subject to the rest ridions on the cover or first page 
I 

Pan of GE.i Aviation Bus.iness 

SERVICE BULLETIN 

(14) Install the 18 tie wrap mounts, Part No. P901546, in groups of three as follows: 

(a) Refer to Figure 2. Make marks on the backplate to show the positions of the tie wrap mounts. 

As an alternative, if available, use the Grommet and Tie Wrap Mount Template, Part No. 

DAPT69-004 7-00. 

(b) Use 100-180 grit, aluminium oxide abrasive paper, to remove the glossy surface finish on the 

backplate where the tie wrap mounts will be installed. 

(c) Apply Acetone or Exxon Actrel 2221 to ali nt fee cloth and fully clean and remove all dust 

from the backplate. 

(d) Apply one drop of L octite, Grade 380E adhesive (P999439), to the bottom of the tie wrap 

mounts, Part No. P901546. 

(e) Remove the self adhesive covers from each tie wrap mount fixing frame. 

(f) Put the tie wrap mount fixing frames in their correct locations and press down on them. 

(g) Press the centre and make sure that the tie wrap mount 'clicked' onto the face of the 

backplate. 

(h) Let the Loctite adhesive, Grade 380E (P999439), cure on each tie wrap mount as specified 

by the manufacturer for temperature and time. 

(i) When the adhesive has cured, hold each tie wrap mount fixing frame with a pair of pliers, and 

with a forward and backward movement remove each tie wrap mount fixing frame from the 

backplate 

0) Repair damage to the paint with gunship black paint to MIL-C-832868. 

(15) Refer toPS 5405-1 . Use ink to write the new part number of the backplate adjacent to the old part 

number as follows: 

Old Part No. 

666000457 

New Part No. 

666000626 

(16) Refer to PS 5405-1. Use ink to write the new part number of the backplate assembly adjacent to the 

old part number as follows: 

Old Part No. 

697071231 

New Part No. 

697037222 

(17) Refer to Figure 3. Attach the ring tongue terminals of the six slip ring de-icer harnesses, Part No. 

697037226, to the slip ring assembly (2-200) with the bolts (2-120) and the washers (2-130). 

NOTE : It is not i mportant which end oft he de-icer harnesses are attached to the slip ring 

assembly. 

(18) Tighten the bolts (2-120). Refer to the Component Maintenance Manual, ASSEMBLY. 

NOTE : There must be no strain on the slip ring de-icer harnesses, Part No. 697037226 after the 

bolts have been tightened. 

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

t•art of GE't Aviation Busint.-ss 

SERVICE BULLETIN 

(19) Refer to Figure 4. Attach the slip ring assembly (2-200) onto the backplate assembly Part No. 

697037222 with their alignment marks aligned. At the same time put the free ends of the slip ring 

de-icer harnesses. Part No. 697037226, through the grommets Part No. P901519 in the backplate. 

Refer to the Component Maintenance Manual, ASSEMBLY. 

(20) Attach the free ends of the slip ring de-icer harnesses, Part No. 697037226 to the terminal 

assemblies Part No. 697037225 on the backplate assembly, Part No. 697037222 as follows: 

(a) If installed, undo and remove the self-locking nuts (3-20) and the washers (2-30) from the 

terminal assemblies, Part No. 697037225. 

(b) Install the ring tongue terminals of the slip ring de-icer harnesses, Part No. 697037226 to the 

terminal assemblies, Part No. 697037225. 

(c) Install the ring tongue terminals of th e de-icer wire harnesses (3-80) to the terminal 

assemblies, Part No. 697037225. 

(d) Install the washers (2-30) and the self-locking nuts (3-20) to the terminal assemblies, 

Part No. 697037225. 

(e) Torque the self-locking nuts. Refer to the Component Maintenance Manual, ASSEMBLY. 

(21) Use the tie wraps Part No. MS3367-4 to attach each of the slip ring de-icer harnesses, Part No. 

697037226 to each of their three tie wrap mounts. Refer to Figure 4. 

(22) Seal the grommet bores with 3M 5300 sealant. 

(23) Install the slip ring and backplate assembly (2-50) to the hub and actuator. Refer to the Component 

Maintenance Manual, ASSEMBLY. 

(24) Refer toPS 5405-1 . Use ink to write the new part number of the slip ring and backplate assembly 

adjacent to the old part number as follows: 

Old Part No. 

697037221 

New Part No. 

697037223 

(25) Refer to CMM 61-10-49. Complete the assembly of the hub, actuator and backplate assembly LRU. 

(26) Do an electrical check of the propeller. Refer to PS5723, para. 11 . 

(27) Install the propeller to the aircraft. Refer to AMM Task 61-10-00-400-801 . 

(28) If necessary, do a dynamic balance of the propeller. Refer To AMM Task 61-10-00-720-801 . 

B. Make a Record 

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

-Write Service Bulletin 08400-61-94 in the propeller log book. 

Jun 14/10 08400-61-94 

Oct 23/12 (Revision 3) PageS 

GE Aviation Systems Ltd Proprietary Information Use o rdisdosure of data con tan ed on this sheet is subject to the rest ridi ons on the cover or first page 
Jun 14/10 

Aug 29/12 (Revision 2) 

GE Aviation Systems Ltd Proprietary Information 

P:ut of GE's Aviation Business 

SERVICE BULLETIN 

Slip ring De-icer Harness 697037226 

Figure 1 

Use ordisdosure of data oontai'led on this sheet is subject to the restrictions on the cover or first page 

0 840061 94-1 A 

08400-61 -94 

Page? 
BACKPLATE 

ASSEMBLY 

697071231 

TIE WRAP MOUNT 

P901546 (QTY 18) 

SECTION A-A 

Pan ol' ~ A\'iation Busint'Ss 

SERVICE BULLETIN 

8--J~ TO 12° 42' 

TERMINAL 

ASSEMBLY 

(4-40) 

29 mm -;-------ti~ 

(1 .142 in) 

SECTION 8-8 

TYPICAL 6 POSITIONS 

EQUALLY SPACED 

084006194-28 

Grommet Holes Terminal Assemblies and Tie Wrap Mounts Locations 

Figure 2 

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Aug 29/12 (Revision 2) Page 8 

GE Aviation Systems Ltd Proprietary Information 

Use or disdosure of data co ntan ed on this sheet is subject to the restrictions on the cover or first page 
I 

J•an.of GE's Aviation Bus.inc:ss 

SERVICE BULLETIN 

Installation of Slip ring De-icer Harnesses to the Slip ring Assembly 

Figure 3 

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Oct 23/12 (Revision 3) Page 9 

GE Aviation Systems Ltd Proprietary Information 

Use ordisdosure of data oontahed on this sheet is subject to the rest ridions on the coverer first page 
C/L BLADE 6 --.... 

TERMINAL 

ASSEMBLY 

(440) REF. 

SELF LOCKING 

NUT (3-20) 

(QTY 12) 

WASHER 

(3-30) (QTY 24) 

( 

BACKPLATE 

666000626 

C/L BLADE 5 

l':t.rt ol" GE's Aviation Bus.incss 

SERVICE BULLETIN 

SLIPRING DE-ICER 

HARNESS 

697037226 (QTY 6) 

~C/LBLADE2 

TERMINAL ASSEMBLY 

697037225 (QTY 12) 

I 

MINATURE TIE MOUNT 

P90146 (QTY 18) 

C/L BLADE 3 

VIEW LOOKING AFT ON BACKPLATE ASSEMBLY 697037222 

BOLT (2-120) (QTY 12) 

WASHER (2-130) (QTY 24) 

SECTION C-C 

BOLT (2-1 00) (QTY 12) 

WASHER (2-110) (QTY 12) 

SLJPRING 

ASSEMBLY 

(2-200) 

VIEW LOOKING FWD ON BACKPLATE 

SUPRING ASSEMBLY NOT SHOWN 

084006194-38 

Installation of Grommets, Tie Wrap Mounts, Terminal Assemblies and Slip ring De-icer Harnesses 

I Figure 4 

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