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### 1 . REASON PartofGE's A\"iatDn Business 

## I SERVICE BULLETIN 

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# 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 Prope llers An son Bu sin ess Park , Ch eltenham Road East, Gloucester, GL2 9QN ENGLAND Telephone: 01452 716000 Facsimile: 01452 716001

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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 Pacifi c 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 Kingd om 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 Av iation 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 , mod ifications , spare parts, designs, or configuration changes or to obta in 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 appea r in any such rep roduction 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 li ke , have been developed and approved for use with this equ ipment and parts that have been manufactured and/or app roved by GE and that have been maintained in accordance with GE techn ical documentation and recommendations . GE has no con t ra ctual or legal obl igation for, nor know lege of, non-GE-approved pa rts and repai rs . 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 BULLETI N 

# 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 nta n ed on th i s 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 BULLETI N 

# 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) wh ich 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. 

# D8400-6 1-A66 Aug 17/11 (Revision 6) Page 3 GE Aviati on System s Ltd Proprietary Inform ation Use or disdosure of data contai1ed on th i s sheet is subject to the rest ridions on the cove r or first page

# I lt8Wirlf Part ofGE's Aviation Busine-ss SERVICE BULLET I N 

# 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 aga inst 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 assemb ly 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 fo r a minimum of 45 minutes before returning the propeller to service . C . Make a Record (1) When the instructions of th is 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 G E Aviation Systems Ltd Proprietary Information Use or disdosure of data co nta il ed on this sh eet i s 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 BULLETI N

DETAIL 

## A 225 mm (8.86 in)



## A 

# ALERT

BUSBAR ASS EMBLIE S (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 cont a i"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 ASS EMBLIE S

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