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1 . REASON 

# ltctWYT Pari of GE·s AviatOn Business 

## I SERVICE BULLETIN 

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# SERVICE BULLETIN SERVICE BULLETIN 08400-61-94 TRANSMITIAL LETIER FOR REVISION N0.2 Dated Aug 29/12



### A. Re-issued at revison 2. Classification changed from controlled service introduction to fully recommended . The service bulletin has been revised to reflect this and to also include additional new parts , procedural changes and illustrations. The format has also been changed in line with the latest style . 2. ACTION A. Remove and destroy existing pages 1 to 4 of the service bulletin and replace with revised pages 1 to 9 dated Aug 29/12 .



# Dowty Propellers Anson Business Park, Cheltenham Road East, Gloucester, GL2 9QN ENGLAND Telephone : 01452 716000 Facsimile: 01452 716001

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# • IDCDW7T

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 BUSBAR 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 B. Concurrent requirements (1) None. C. Reason (1) (2) 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. Service bulletin D8400-61-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 ofany 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 . 

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# 08400-61-94 Jun 14/10 Aug 29/12 (Revision 2) Page 1 of 9

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### 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) Recommended - Customers can request this service bulletin to be implemented free of charge at the next major inspection at Dowty's repair facilities . Customers who would like to return units before this time can contact Dowty to discuss a program of managed returns on a chargeable basis . (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.21J.008. (2) The technical content of this service bulletin has been reviewed and accepted by Bombardier Aerospace. G. Manpower 

# 1 (1) This service bulletin will take approximately 3 hours to complete . H. Weight and Balance (1) None. 

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### 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 

# I (1) Dowty Propellers Component Maintenance Manual61-10-49. (2) Dowty Propellers Propeller Maintenance Manual Part 2, Chapter 61-10-46. (3) Bombardier Aerospace 0400 Aircraft Maintenance Manual. Jun 14/10 

# 08400-61-94 Aug 29/12 (Revision 2) Page 2 GE Aviation Systems ltd Proprietary Information Use o r disdosure of data oo ntan ed on thi s sheet is subject to the restridions on the cover or first page

# ltCDWifT l1:u1 ofGE's A viotion**usin~s** SERVICE BULLETI N



### M . Interchangeability or lntermixability of Parts (1) Pre and Post SB D8400-61-94 propellers are interchangeable. 

# I 2. Material Information 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 . 

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B. Material Necessary 

## 1 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 

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

Jun 14/10 

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# I t•art ofGE'sAvi :uion Busine-ss 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) Remove the propeller from the aircraft. Refer to AMM Task 61-10-00-000-801 . (2) Remove the slip ring and backplate assembly (2-50) from the hub and actuator. Refer to the Component Maintenance Manual , DISASSEMBLY. (3) 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). (4) Remove the slip ring assembly (2-200) from the backplate assembly (4-20). Refer to the Component Maintenance Manual , DISASSEMBLY. (5) 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) . (6) Refer to Figure 3. Attach the ring tongue terminals of the six sl ip ring de-icer harnesses , Part No. 697037226 , to the slip ring assembly (2-200) with the bolts (2-120) and the washers (2-130). Do not fully tighten the bolts (2-120) at this step . NOTE : It is not important which end of the de-icer harnesses are attached to the slip ring assembly. (7) Remove the ring tongue terminals of the de-icer wire harnesses (3-80) , from the terminal assemblies (4-40) . (8) 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) . (9) 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. (1 0) Refer to Figure 2. Use a 15 mm (0 .590 in) drill or hole cutter and make six holes in the backplate (for the grommets, Part No. P901519) at the positions shown . As an alternative, if available , use 

# 1 the Grommet and Tie Wrap Mount Template, Part No. DAPT69-0047-00 to get the hole positions. (11) (12) (13) (14)

Jun 14/10 Locally clean the backplate as necessary to remove all unwanted material. Refer to the Component Maintenance Manual, CLEANING. Apply Acetone or Exxon Actrel 2221 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 3. Install the six grommets Part No. P901519 into the holes. 

# 08400-61-94 Aug 29/12 (Revision 2) Page4 G E Aviation Systems Ltd Proprietary Information Use o r disdosure of data contan ed on thi s sheet is su**b~ct** to the restrictions on the cover or first page

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(16) 

# IDctWirT Pln ofGE's A\'iation Husim.-ss SERVICE BULLETIN

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. DAPT69-0047-00 . (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 a lint fee cloth and fully clean and remove all dust from the backplate. (d) Apply one drop of Loctite, 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 

### U) Repair damage to the paint with gunship black paint to MIL-C-83286B . 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 (17) Refer to PS 5405-1 . Use ink to write the new part number ofthe backplate assembly adjacent to the old part number as follows: Old Part No. 697071231 New Part No. 697037222 (18) Refer to Figure 3. Put 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 . Make sure that the ends ofthe slip ring de-icer harnesses , Part No. 697037226 are free to move on the bolts (2-120). (19) Tighten the bolts (2- 120). Refer to the Component Maintenance Manual , ASSEMBLY. (20)

Jun 14/10 NOTE : There must be no strain on the slip ring de-icer harnesses , Part No. 697037226 after the bolts have been tightened . Attach the slip ring assembly (2-200) to the backplate assembly, Part No. 697037222 . Refer to the Component Maintenance Manual , ASSEMBLY. 

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### (21) 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 the 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. (22) 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 3. (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. New Part No. 697037221 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. 

## 1 (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 

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### Jun 14/10 Aug 29/12 (Revision 2) GE Aviation Systems Ltd Proprietary Information 1•an ofCiE'l': Avintion Husim. •ss SERVICE BULLETIN



### Slip ring De-icer Harness 697037226 Figure 1

Use o rdi sdosure of data co ntai1 ed on this sheet is su bj;!ct to the rest ridions on the cover or first page 084006194-1A 

# 08400-61-94 Page 7• I

SE RVICE BU LLETIN

14,5 GAUGE REF .

SECTION 

## A-A TERMINAL ASSEMBLY (4-40)

29 mm - +-----+i'*" (1 . 142 in)

SECTI ON 

### 8-8 TYPICAL 6 POSIT IONS

EQUALLY SPAC ED 0 84006194-28 

### Grommet Holes Terminal Assemblies and Tie Wrap Mounts Locations Figure 2 Jun 14/10 

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# • •

C/L BLADE 6 --._ TERMINAL ASSEMBLY (4-40) REF . SELF LOCKING NUT (3-20) (QTY 12) WASHER (3-30) (QTY 24) 

# ( BACKPLATE 666000626

C/L BLADE 5 

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SLIPRING DE-ICER HARNESS 697037226 (QTY 6)

# tlr.~ _,-- C/L BLADE 2

C/L BLADE 4 

# I RIVET (4-30) (QTY24)

MINATURE TIE MOUNT P90146 (QTY 18) DE-ICER WIRE

HARNESS (3-80) (QTY 6) 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 (2-100) (QTY 12) WASHER (2-110) (QTY 12)

SLIPRING ASSEMBLY

(2-200)

084006194-38 

### Installation of Grommets, Tie Wrap Mounts, Terminal Assemblies and Slip ring De-icer Harnesses Figure 3 Jun14/10 

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