# D

S.B. 84 ---32 ---121 Page 1 of 10 27 May 2013 NB 

# SERVICE BULLETIN Customer Support
ATA SYSTEM: 3211 NUMBER: 84 ---32 ---121 

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

SUBJECT: Landing Gear --- MLG Stabilizer Brace Assembly --- Lock Link Assembly --- Inspection/Rectification

1. PLANNING INFORMA TION A. Effectivity Aircraft Affected: In ---Service: DHC ---8 Aircraft Models 401 and 402 Serial Numbers 4001, 4003 thru 4454. Production: The gap, torque and lubrication have been verified on DHC ---8 Aircraft Serial Numbers 4455 and subsequent per ModSum 4 ---168098.
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.

### SERVICE BULLETIN 84 ---32 ---121

S.B. 84 ---32 ---121 Page 2 of 10 27 May 2013 NB Spares Affected: None B. Reason Problem: An operator was unable to achieve a down and locked indication on one landing gear. Cause: Investigation determined the cause as lack of lubrication and possible over ---torque of the lock link apex pin retaining bolt. Solution: This service bulletin provides the instructions to inspect the MLG lock link assembly to make sure the torque of the lock link apex joint is within the specified limits and to make sure the stabilizer brace joint is properly lubricated. C. Description The procedures in this service bulletin give the instructions to do the tasks that follow: --- aircraft is put into standard configuration for maintenance --- nose landing gear lock is engaged --- main landing gear lock pins are installed thru each main gear --- main landing gear doors are opened and locked --- hydraulic pressure system is depleted --- aircraft electrical power is removed --- work platforms or ladders are positioned as required to gain access to the stabilizer brace in left and right wheel wells and properly grounded --- MLG Stabilizer Brace Assembly lock link apex joint is checked for gap, and if necessary, lubricated --- if lock links need to be retorqued to meet gap requirement, aircraft is lifted on jacks --- close out.

### SERVICE BULLETIN 84 ---32 ---121

S.B. 84 ---32 ---121 Page 3 of 10 27 May 2013 NB D. Compliance Bombardier Inc. highly recommends incorporation of this service bulletin at the earliest opportunity unless otherwise directed by the operator’s airworthiness authority. Transport Canada Airworthiness Directive Pending. 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. This service bulletin does not affect Airworthiness Limitations (AWLs) or Damage Tolerance Inspections (DTIs). F. Manpower It will take an estimated 3 man ---hours to complete this service bulletin. The breakdown of the man ---hours is shown in the table that follows:
TASK MAN ---HOURS Job Set ---Up 0.50 Procedure 2.00 Test / RTS 0.00 Close ---Out 0.50 For any on---site labor assistance, please speak with a Fleet Services representative for a quote. The Fleet Services group can be contacted via the Q Series Technical Help Desk by telephone at 416---375---4000 or email at: thd.qseries@aero.bombardier.com G. Material --- Price and Availability None

### SERVICE BULLETIN 84 ---32 ---121

S.B. 84 ---32 ---121 Page 4 of 10 27 May 2013 NB H. Tooling --- Price and Availability None I. Weight and Balance None J. Electrical Load Data Not affected K. Publications Affected None L. References The initial issue of this service bulletinwas prepared to the engineering and related data that follows: ModSum 4N168098 Rev. ‘B’ ModSum 4 ---168098 Rev. ‘A’ PCA 44512 Revision 0 (for internal reference only) Goodrich Service Bulletin 46400 ---32 ---111 Transport Canada Airworthiness Directive Pending. 2. MATERIAL INFORMA TION A. Parts Required Per Aircraft None B. Parts Required to Modify Spares None C. Special Tools and Equipment Required None D. Existing Parts Accountability None

### SERVICE BULLETIN 84 ---32 ---121

S.B. 84 ---32 ---121 Page 5 of 10 27 May 2013 NB 3. ACCOMPLISHMENTINSTRUCTIONS A. Job Set ---Up (1) Engage the nose gear ground lock (refer to AMM TASK 10 ---11 ---00 ---400 ---801). (2) Install the lock pins on the main landing gear (refer to AMM TASK 10 ---11 ---00 ---400 ---802). (3) Open and lock the main landing gear doors (refer to applicable instructions in AMM TASK 32 ---00 ---00 ---840 ---801). (4) Deplete all hydraulic pressure in the No. 1, No. 2 and No. 3 system (refer to AMM TASK 29 ---00 ---00 ---863 ---802 and TASK 29 ---00 ---00 ---863 ---804). (5) Placard and select all aircraft electrical power to OFF. Obey all relevant WARNINGS and CAUTIONS (refer to AMM TASK 24 ---00 ---00 ---861 ---802 and TASK 24 ---00 ---00 ---910 ---801). (6) Install a warning sign on the external hydraulic connection. (7) Install a warning sign on the hydraulic PTU Control Switch (on main instrument panel). (8) Set up the work platforms or ladders asrequired to gain access to main landing gear stabilizer brace assemblies (refer to Figure 1). Make sure the work platforms or ladders are electrically grounded. B. Procedure

WARNING: MAKE SURE THAT THERE IS NO PRESSURE IN THE HYDRAULIC SYSTEM. IF YOU DO NOT DO THIS YOU CAN CAUSE INJURIES TO PERSONS AND DAMAGE TO THE EQUIPMENT. (1) Inspect the stabilizer brace lock link apex joint in accordance with the instructions given in SECTION II --- ACCOMPLISHMENT INSTRUCTIONSof attached Goodrich Service Bulletin 46400 ---32 ---111.

### SERVICE BULLETIN 84 ---32 ---121

S.B. 84 ---32 ---121 Page 6 of 10 27 May 2013 NB (2) If gap is 0.001 inch (0.025 mm) or greater, continue with step (4). (3) If gap is less than 0.001 inch (0.025 mm), do as follows (refer to Figure 2): (a) Lift aircraft on jacks (refer to applicable instructions in AMM TASK 07 ---10 ---00 ---582 ---801). (b) Remove and discard cotter pin MS24665 ---155. (c) Loosen nut MS14145L4 at bolt NAS6204 ---32D on MLG Stabilizer Brace. NOTE: Loosen nut to zero torque. Do not remove nut MS14145L4 from bolt NAS6204 ---32D.
CAUTION: DO NOT EXCEED MAXIMUM TORQUE VALUE OF 30 LBF IN (3.4 NM). IF MAXIMUM TORQUE IS EXCEEDED THE LOCK LINK FUNCTION MAY BE AFFECTED. (d) Torque nut MS14145L4 to 20 lbf in (2.3 Nm) and continue to tighten nut to achieve cotter pin alignment. NOTE: Torque value is in addition to run on torque. NOTE: If maximum torque value is obtained before cotter pin alignment, loosen nut until alignment is achieved. NOTE: It is permissible to use washer NAS1149C0416R in lieu of washer NAS1149C0432R under the nut to aid in cotter pin alignment. (e) Inspect lock link apex joint for clearance. If clearance is still less than 0.001 inch (0.025 mm), contact Technical Help Desk by telephone at 416---375---4000 or email at thd.qseries@aero.bombardier.com for approved disposition/action. (f) If clearance is 0.001 inch (0.025 mm) or greater, install cotter pin MS24665 ---155. (g) Make sure LH and RH target bracket assemblies are secure. (h) Confirm proximity/target gap is within limits (refer to CMM 32 ---11 ---04 ASSEMBLY). If gap is not within limits, adjust the proximity sensor (refer to applicable instructions in AMM TASK 32 ---61 ---06 ---830 ---801).

### SERVICE BULLETIN 84 ---32 ---121

S.B. 84 ---32 ---121 Page 7 of 10 27 May 2013 NB (i) Lower the aircraft and remove the jacks (refer to applicable instructions in AMM TASK 07 ---10 ---00 ---582 ---801). (4) Lubricate the stabilizer brace lock link apex joint (refer to applicable instructions in AMM TASK 12 ---20 ---01 ---640 ---803). (5) Vibro ---peen accomplishment of Goodrich Service Bulletin 46400 ---32 ---111 and date accomplished in MOD STATUS field of nameplate. (6) Repeat steps (1) to (5) for the opposite stabilizer brace lock link apex joint. C. Close Out (1) Remove all tools and equipment from the work area. (2) Unlock and close the landing gear doors (refer to AMM TASK 32 ---00 ---00 ---840 ---802 ). (3) On completion of this service bulletin, make the following entry in the appropriate logbooks: “Service Bulletin 84 ---32 ---121 (i.e. Landing Gear --- MLG Stabilizer Brace Assembly --- Lock Link Assembly --- Inspection/Rectification) accomplished.”

### SERVICE BULLETIN 84 ---32 ---121

S.B. 84 ---32 ---121 Page 8 of 10 27 May 2013 NB MLG Stabilizer Brace Assembly --- Location Figure 1 AREA OF INSPECTION/RECTIFICATION

### SERVICE BULLETIN 84 ---32 ---121

S.B. 84 ---32 ---121 Page 9 of 10 27 May 2013 NB Lock Link Apex Joint --- Gap Check Figure 2 NAS6204 ---32D RH TARGET

PUSH AFT LOCK LINK TO ONE SIDE. MINIMUM GAP 0.001 IN. (0.025 MM). LOCK PIN APEX PIN WASHER BOLT LH TARGET BRACKET ASSEMBLY STABILIZER BRACE

NAS1149C0432R NUT MS14145L4 COTTER PIN MS24665 ---155 BRACKET ASSEMBLY

### SERVICE BULLETIN 84 ---32 ---121

S.B. 84 ---32 ---121 Page 10 of 10 27 May 2013 NB 

### This Page Intentionally Blank 1