# D

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# SERVICE BULLETIN Customer Support
ATA SYSTEM: 2822 NUMBER: 84 ---28 ---05


### BOMBARDIER AEROSPACE REGIONAL AIRCRAFT CONSIDER THIS SERVICE BULLETIN TO BE PARTICULARLY SIGNIFICANT AND URGES OPERATORS TO PROMPTLY EVALUATE THE CONTENTS

SUBJECT: Fuel --- Fuel Feed to APU --- Replacement of Couplings in Center Wing Left Side --- SFAR 88 --- ModSum 4 ---901425

1. PLANNING INFORMA TION A. Effectivity Aircraft Affected: In ---Service: DHC ---8 Aircraft Models 401 and 402 Serial Numbers 4003, 4004, 4006 and 4008 thru 4118 with prerequisite ModSum 4 ---302000 (APU option) Verification: ModSum 4 ---901425 has been installed on DHC ---8 Aircraft Model 402 Serial Number 4006. NOTE: The instructions in this Service Bulletin are only applicable to the systems and parts installed at the time of delivery on the aircraft or as changed by Bombardier Aerospace Service Bulletin(s). Before you do this bulletin, examine all STC or equivalent action changes to make sure this bulletin can be completed. Spares Affected: None

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.. .. .. .. B. Reason Problem: Two existing couplings (p/n BO305025A08) one installed immediately before and the second installed immediately after the APU shut ---off valve (engine fuel feed installation --- center wing left side) require replacement in order to meet SFAR 88 (Special Federal Aviation Regulation) requirements. Solution: Two existing self bonded couplings (p/n BO305025A08) are replaced with new self bonded couplings (p/n BO305082A08) that have an increased electrical current capacity. The new couplings are designed to enhance fuel tank system safety and meet the FAA certification requirements given in the SFAR 88 regulations. C. Description The procedures in this service bulletin give the instructions to do the tasks that follow: --- lock pins are installed thru each main gear and main gear door mechanism --- the nose gear ground lock is engaged --- the aircraft is pressure defueled --- the aircraft electrical system is de ---energized --- work platforms or ladders are setup as required (left wing inboard section) --- center wing access panels 521BT and 522AT are removed --- existing couplings BO305025A08 (qty. 2) and related preformed packing are removed --- new couplings B0305082A08 (qty. 2) and preformed packings MS29513 ---015 (qty. 4) are installed --- close ---out is accomplished. D. Compliance Bombardier Inc. highly recommends that ModSum 4 ---901425 be incorporated at the earliest opportunity unless otherwise directed by the operator’s airworthiness authority. An Airworthiness Directive from Transport Canada is pending.

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.. .. .. .. E. Approval The technical content of this Service Bulletin has been approved under the authority of the Transport Canada Civil Aviation (TCCA) Design Approval Organization No: DAO #93 ---Q ---02. F. Manpower It will take less than one man ---hour to replace the two fuel couplings at the fuel shutoff valve in the left wing if this service bulletin is incorporated concurrently with service bulletin 84 ---57 ---09 (ModSum 4 ---126330). All costs to incorporate this modification are the responsibility of the Operator G. Material --- Price and Availability ModKit 8MK4259 ---001 is available through the Customer Accounts Service Team at Bombardier Aerospace Regional Aircraft division. Operators should submit a purchase order specifying aircraft serial number(s) to: Bombardier Aerospace Customer Accounts Services Team (Mail Stop N11 ---32) 123 Garratt Blvd. Downsview Ontario Canada M3K ---1Y5 Facsimile: (416) 375 ---3060 Telephone : (416) 375 ---3920
Kit Number Description Price (US$) Delivery 8MK4259 ---001 Couplings Fuel System for APU --- Wing Left Hand --- SFAR 88 Quoted at time of order Will be given at time of order

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.. .. .. .. H. Tooling --- Price and Availability None I. Weight and Balance None J. Electrical Load Data Not affected K. Publications Affected Dash 8 Illustrated Parts Catalogue PSM 1 ---84 ---4

.................... ModSums Manual PSM 1 ---84 ---12

.................................. L. References The initial issue of this service bulletin was prepared to the engineering drawings and related data that follows: DRAWING SHEET REV 8MK4259 1

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8Z4596 1 A ModSum 4Q901425 Rev. ‘B’ ModSum 4 ---901425 Rev. ‘B’ PCA 40933 Revision 2 (for internal reference only) Transport Canada Airworthiness Directive Pending 2. MATERIAL INFORMA TION A. Parts Required Per Aircraft (1) Modification Kit 8MK4259 ---001 (2) Detailed Kit Content:

Quantity Per Kit ---001 Part Number Description Remarks

4 MS29513 ---015 Preformed packing 2 B0305082A08 Coupling NOTE: This service bulletin is self ---contained (illustrated). No drawings will be supplied.

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.. .. .. .. (3) In addition to the above part(s), the following material(s) are required for the completion of this service bulletin and may be procured as single items from Bombardier Aerospace Regional Aircraft or purchased directly from industry
sources.

Part Number Qty. Per Aircraft Description Remarks
04 ---14 1 ounce Petroleum Jelly --- Petrolatum Refer to Consumable Products Manual PSM 1 ---84 ---18, B. Parts Required to Modify Spares None C. Special Tools and Equipment Required None D. Existing Parts Accountability The following parts may be affected by this service bulletin. Indented parts are components of the next higher assembly. The quantity (Qty.) column lists the quantity that may be affected per aircraft for non ---indented parts and the quantity per next higher assembly for indented parts.
Existing Part Number Description Qty. IC DC New Part Number PNC B0305025A08 Coupling 2 C DIS B0305082A08 S IC Interchangeability Code A Not interchangeable. B Removed Part. No direct replacement. C Conditionally Interchangeable. Inst allation of superseded part negates the intent of this service bulletin.

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.. .. .. .. DC Disposition DIS Discard Part. MUI Multiple Usage Item: Return to stock if serviceable. RWK Rework existing part in accordance with this service bulletin. RWI Rework existing part per ..... SAL Salvage. Return to operator’s stores for salvage consideration. PNC Part Number Code N No equivalent Bombardier Inc. part number for reworked part. Indicate on part that this service bulletin has been accomplished. R Part number after rework. S Superseding part number. X Reworked part and superseding part are functionally and physically equivalent but not identical. 3. ACCOMPLISHMENT INSTRUCTIONS A. Job Set ---Up

WARNING: OBEY ALL THE FUEL SAFETY PRECAUTIONS WHEN YOU DO WORK ON THE FUEL SYSTEM AND/OR A FUEL SYSTEM COMPONENT. IF YOU DO NOT YOU CAN CAUSE INJURIES TO PERSONS AND/OR DAMAGE TO EQUIPMENT. (1) Make sure that lock pins are installed thru each main gear and main gear door mechanism. (2) Make sure the nose gear ground lock is engaged. (3) Pressure defuel the applicable fuel tank ( Refer to TASK 12 ---10 ---28 ---650 ---802 ). (4) Make sure to de ---energize the aircraft electrical system (refer to AMM TASK 24 ---00 ---00 ---861 ---802). (5) Set up work platforms or ladders around and/or under the inboard section of the left wing to permit access to access panels 521BT and 522BT (refer to Figure 1). Make sure that the work platforms or ladders are electrically grounded. (6) Make sure to obey the fuel system safety precautions (refer to AMM TASK 28 ---00 ---00 ---910 ---801). WARNING: MAKE SURE THAT THE FUEL TANK IS DRAINED BEFORE YOU REMOVE THE ACCESS PANELS. IF YOU DO NOT DO THIS, YOU CAN

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.. .. .. .. CAUSE DAMAGE TO THE WING STRUCTURE. (7) Remove the center wing access panels that follow (refer to AMM TASK 57 ---11 ---01 ---000 ---801 and TASK 57 ---11 ---06 ---000 ---802): ACCESS DESIGNATION

521BT Dry Bay Fuel Access Panels 522AT Center Wing Fuel Access Panel (8) Make sure to remove the fuel fumes from the fuel tank (refer to AMM TASK 28 ---10 ---00 ---840 ---802). B. Procedure (1) Locate the APU shut ---off valve (SOV) in the left side of the center wing section (refer to Figures 1 and 2). (2) Remove and discard the existing co upling B0305025A08 and related packings located on each side of the SOV (refer to Figure 2). NOTE: If the sleeve and o --- rings of a B0305025A08 coupling are not disturbed. It is acceptable to replace the clam shell only without replacing the sleeve and o --- rings. (3) Lubricate new packings MS29513 ---015 (qty. 4) with petroleum jelly. (4) Install one packing MS29513 ---015 in position at the end of each tube assembly and to the SOV (refer to Figure 3). (5) Carefully connect the tubes and the SOV together with new couplings B0305082A08 (qty. 2) and sleeves. C. Close Out (1) Remove all unwanted material from the rework area. (2) Install the center wing access panels that follow (refer to TASK 57 ---11 ---01 ---400 ---801 and TASK 57 ---11 ---06 ---400 ---802): ACCESS DESIGNATION

521BT Dry Bay Fuel Access Panels 522AT Center Wing Fuel Access Panel (3) Remove all tools and equipment from the work area.

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.. .. .. .. (4) On incorporation of this ModSum, make an entry that conforms to local regulatory requirements in the applicable logbook(s). Enter component serial numbers if applicable. Enter this ModSum number only after complete incorporation of all work defined in this service bulletin.

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.. .. .. .. Figure 1 DETAIL A SEE FIGURE 2 522BT 521AT

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.. .. .. .. Figure 2NEW COUPLING B0305082A08 (2 REQD)PREFORMED PACKING MS29513 ---015 (4 REQD)APU SHUT ---OFF VALVEREAR SPARREF

DETAIL ATUBE ASSYTUBE ASSYREFSEE FIGURE 3 FOR DETAIL VIEWREFEXISTING COUPLING BO305025A08 (QTY 2)AND PREFORMED PACKINGS (QTY4) REMOVED

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.. .. .. .. Figure 3 TUBE ASSY

TUBE ASSY SHUT ---OFF VALVE PACKINGS MS29513 ---015 COUPLING AND SLEEVE B0305082A08

(2 REQD)

COUPLING AND SLEEVE B0305082A08 PACKINGS MS29513 ---015

(2 REQD) SOV CONNECTOR SOV ACTUATOR

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