Landing Gear − Brake System − Inspection of the Accumulator Screw−Caps (P/N 0860204001)

These pages transmit: Revision D of Alert Service Bulletin A670BA−32−021, pages 1 thru 21, dated Dec 22/2010 and Revision A of Appendix A pages A1 thru A9, dated Oct 18/2007.
The changes in this revision have no effect on aircraft that have incorporated a previous issue of this service bulletin

Reason:

Revised Planning Information, paragraph 1., to: Remove aircraft serial numbers 10315 thru 10999, 15233, 15234, 15239, and 15260 thru 15990 from the effectivity of the service bulletin. Add a note in Compliance paragraph 1.D. Add Bombardier Regional Jet Series All Operator Message (AOM), No. 614, in References paragraph 1.K.
This revision also includes small editorial changes that do not have an effect on the technical content.

Document Instructions: Discard the copy of Alert Service Bulletin A670BA−32−021, Revision C, dated Jul 27/2010. Replace with the copy attached. 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 1 of 2 Dec 22/2010 

# SERVICE BULLETIN REVISION TRANSMITTAL SHEET

CL−600−2C10, CL−600−2D15, CL−600−2D24 and CL−600−2E25 CANADAIR REGIONAL JET (CRJ) AIRCRAFT

SUBJECT:KEEP TACTAIR SERVICE BULLETIN SB0860204001−32−02.
Service Bulletin History: Initial issue, dated Nov 21/2006. Revision A, dated Mar 07/2007. Revision B, dated Oct 18/2007. Revision C, dated Jul 27/2010. 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 2 of 2 Dec 22/2010 

### REVISION TRANSMITTAL SHEETLanding Gear − Brake System − Inspection of the Accumulator Screw−Caps (P/N 0860204001)

1. PLANNING INFORMATION A. Effectivity (1) Aircraft Affected: Service Bulletin: CL−600−2C10 Canadair Regional Jet (CRJ) Aircraft Serial Numbers 10003 thru 10314.
Production: There is no production effectivity.
Service Bulletin: CL−600−2D15 Canadair Regional Jet (CRJ) and CL−600−2D24 Canadair Regional Jet (CRJ) Aircraft Serial Numbers 15001 thru 15232, 15235 thru 15238, and 15240 thru 15259.
Production: There is no production effectivity.

NOTE : The instructions in this service bulletin are only applicable to the systems and parts installed at the time of delivery of the aircraft or as changed by Bombardier Aerospace Service Bulletin. Before you do this bulletin, examine all STC, STA or equivalent action changes to make sure this bulletin can be completed. ATA SYSTEM: 32−43 NUMBER: A670BA−32−021

S.B. A670BA−32−021 Page 1 of 21 Nov 21/2006 Revision D, Dec 22/2010 

# ALERT SERVICE BULLETIN

Technical Publications

THIS SERVICE BULLETIN IS SENT TO EACH OPERATOR. IF THE OPERATOR HAS LEASED AIRCRAFT, THIS SERVICE BULLETIN MUST BE SENT TO THE LESSEE. IF THE OPERATOR HAS SOLD AIRCRAFT OR TRANSFERRED SPARES IN THE LAST SIX MONTHS, THIS SERVICE BULLETIN MUST BE SENT TO THE NEW OWNER, UNLESS CONFIRMATION WAS RECEIVED THAT BOMBARDIER COMMERCIAL AIRCRAFT DIVISION HAS INCLUDED THE NEW OPERATOR ON THE DISTRIBUTION LIST.

SUBJECT:B. Reason (1) Condition It is possible for the screw−caps of the brake accumulator to have cracks in the inner shoulder. This can cause the screw−cap to rupture and cause damage to the aircraft structure and systems. (2) Evidence Two screw−caps ruptured and disconnected from the gas side of the outboard brake accumulator (system No. 2) on two CL−600−2B19 aircraft. (3) Objective/Benefit This service bulletin gives the procedure to do a detailed inspection and an ultrasonic inspection on the screw−caps of the accumulator of No. 2 and No. 3 brake systems. This will prevent damage to the accumulators, aircraft structure and systems. C. Description This service bulletin is divided in two parts: PART A and PART B. PART A − Detailed Inspection of the Accumulator Screw−Caps Circuit breakers are opened. The electrical power is removed. The hydraulic pressure is released from systems No. 2 and No 3. The nitrogen pressure is bled from the inboard and outboard brake accumulators. A detailed inspection is done on the screw−caps of the accumulators. Circuit breakers are closed. The servicing of the brake accumulators is done with nitrogen. The operational test is done on the brake system. PART B − Ultrasonic Inspection of the Accumulator Screw−Caps Circuit breakers are opened. The electrical power is removed. The hydraulic pressure is released from systems No. 2 and No. 3. The nitrogen pressure is bled from the inboard and outboard brake accumulators. The inboard and outboard brake accumulators are removed. An ultrasonic inspection is done on the screw−caps of the accumulators. Circuit breakers are closed. The brake accumulators are installed. Servicing of the brake accumulators is done with nitrogen. The operational test is done on the brake system. 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 2 of 21 Nov 21/2006 Revision D, Dec 22/2010D. Compliance Alert Service Bulletin. NOTE : It is not necessary to do this service bulletin when Service Bulletin 670BA−32−028, Landing Gear − Brake System − Replacement of Accumulator P/N 0860204001 by P/N 90006691, is done Bombardier Aerospace recommends that this service bulletin be done as shown in the table below, unless otherwise directed by the airworthiness authority of the operator: NOTE : The letter ‘T’ added at the end of the serial number of accumulators P/N 0860204001 identifies that the new screw−caps were installed as shown in Tactair Service Bulletin SB0860204001−32−02. 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 3 of 21 Nov 21/2006 Revision D, Dec 22/2010APPLICABLE COMPLIANCE INSPECTION RESULTS ACTION

For inboard and outboard brakes: Accumulators P/N 0860204001 with serial numbers without letter ‘T’ at the end (For the list of serial numbers see TABLE 1 and the note below). For accumulators that have 4500 flight cycles or less, it is necessary to do PART A of this service bulletin before accumulators have 5000 flight cycles. If a crack is found during the detailed inspection (PART A), it is necessary to replace the accumulator before next flight.
The crack must be identified by an ultrasonic inspection described in PART B. It is necessary to repeat the detailed inspection (PART A) every 500 flight cycles from the initial inspection. Or
It is not necessary to do or repeat PART A if PART B is done. For accumulators that have more than 4500 flight cycles, it is necessary to do PART A of this service bulletin no more than 500 flight cycles from the issue date on this service bulletin.
For accumulators that have 3000 flight cycles or less, it is necessary to do PART B of this service bulletin before accumulators have 5000 flight cycles. If a crack is found during the ultrasonic inspection (PART B), it is necessary to replace the accumulator before next flight. It is necessary to do PART B of this service bulletin every 1500 flight cycles from the initial PART B inspection. For accumulators that have more than 3000 flight cycles, it is necessary to do PART B of this service bulletin before 2000 flight cycles from the issue date of this service bulletin. 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 4 of 21 Nov 21/2006 Revision D, Dec 22/2010APPLICABLE COMPLIANCE INSPECTION RESULTS ACTION

For accumulators P/N 0860204001 with serial numbers with letter ‘T’ at the end. It is not necessary to do this service bulletin.

TABLE 1

60204−0001 thru 60204−0006 60204−0008 thru 60204−0047 60204−0049 thru 60204−0077 60204−0080 thru 60204−0088 60204−0090 thru 60204−0102 60204−0104 thru 60204−0111 60204−0113 thru 60204−0118 60204−0120 thru 60204−0122 60204−0124 thru 60204−0132 60204−0134 thru 60204−0140 60204−0142 60204−0144 thru 60204−0151 60204−0154 thru 60204−0163 60204−0165 thru 60204−0166 60204−0169 thru 60204−0177 60204−0179 thru 60204−0192 60204−0194 thru 60204−0197 60204−0200 thru 60204−0204 60204−0207 thru 60204−0219 60204−0221 thru 60204−0223 60204−0225 thru 60204−0226 60204−0228 60204−0230 thru 60204−0237 60204−0239 thru 60204−0256 60204−0258 thru 60204−0259 60204−0262 thru 60204−0263 60204−0265 thru 60204−0266 60204−0270 thru 60204−0275 60204−0277 thru 60204−0279 60204−0283 thru 60204−0286 60204−0288 thru 60204−0295 60204−0299 thru 60204−0314 60204−0316 60204−0319 thru 60204−0335 60204−0337 thru 60204−0338 60204−0340 thru 60204−0342 60204−0344 thru 60204−0350 60204−0352 thru 60204−0353 60204−0355 thru 60204−0394 60204−0396 thru 60204−0415 60204−0417 thru 60204−0454 60204−0457 thru 60204−0463 60204−0465 60204−0467 thru 60204−0477 60204−0479 thru 60204−0488 60204−0490 thru 60204−0507 60204−0509 60204−0511 thru 60204−0550 60204−0552 thru 60204−0555 60204−0557 thru 60204−0573 60204−0575 thru 60204−0577 60204−0579 thru 60204−0582 60204−0584 thru 60204−0621 60204−0623 thru 60204−0643 60204−0645 thru 60204−0647 60204−0649 thru 60204−0661 60204−0663 thru 60204−0682 60204−0684 thru 60204−0686 60204−0688 60204−0690 thru 60204−0699 60204−0701 thru 60204−1999 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 5 of 21 Nov 21/2006 Revision D, Dec 22/2010NOTE : For serial numbers listed in TABLE 2 below, the new screw−caps were installed by Tactair but it is necessary to incorporate Tactair Service Bulletin SB0860204001−32−02 to add the letter ‘T’ at the end of the serial numbers.

TABLE 2

60204−0007 60204−0048 60204−0078 60204−0079 60204−0089 60204−0103 60204−0112 60204−0119 60204−0123 60204−0133 60204−0141 60204−0143 60204−0152 60204−0153 60204−0164 60204−0167 60204−0168 60204−0178 60204−0193 60204−0198 60204−0199 60204−0205 60204−0206A 60204−0220 60204−0224 60204−0227 60204−0229 60204−0238 60204−0257 60204−0260 60204−0261 60204−0264 60204−0267 60204−0268 60204−0269 60204−0276 60204−0280 60204−0281 60204−0282 60204−0287A 60204−0296 60204−0297 60204−0298 60204−0315A 60204−0317 60204−0318 60204−0336 60204−0339 60204−0343 60204−0351 60204−0354 60204−0395 60204−0416 60204−0455 60204−0456 60204−0464 60204−0466 60204−0478 60204−0489 60204−0508 60204−0510 60204−0551 60204−0556 60204−0574 60204−0578 60204−0583 60204−0622 60204−0644 60204−0648 60204−0662 60204−0683 60204−0687 60204−0689 60204−0700 60204−2000 thru 60204−2598

This service bulletin does not affect Airworthiness Limitations (AWLs) or Damage Tolerance Inspections (DTIs). E. Approval The technical content of this service bulletin has been approved under the authority of the TCCA Design Approval Organization No: DAO #93−Q−02. F. Manpower The man−hours given below are an estimate for direct labor done by an experienced crew on an aircraft prepared for maintenance. These estimates do not include the time necessary for: − Administrative functions such as planning, liaison, familiarization, and report writing. − Non productive elapsed time such as rest time, having meals, and crew shift changes. − Elapsed time such as for paint to dry, sealant to cure, and fuel tank venting. 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 6 of 21 Nov 21/2006 Revision D, Dec 22/2010− Preparation for modification (unless specified in the accomplishment instructions) such as cleaning and getting parts, tools, consumables, and ground equipment. − Quality assurance inspections, troubleshooting and/or correction of discrepancies found when a task is done. − All other activities that are not considered by Bombardier Aerospace as directly related to the accomplishment of this procedure. NOTE : For on−site labor assistance, please speak with a Fleet Services representative for a quote. The Fleet Services team can be contacted via the CRC at 514−855−8500 or email at thd.crj@aero.bombardier.com. PART A − Detailed Inspection of the Accumulator Screw−Caps It will take an estimated 3.0 man−hours to complete PART A of this service bulletin. The man−hours are divided as shown in the table that follows:

TASK MAN−HOURS MAX. PERSONS ELAPSED TIME
(1) Job Set−Up 1 1 1 (2) Procedure 0.5 1 0.5 (3) Test 1 2 0.5 (4) Job Close−Out 0.5 1 0.5

PART B − Ultrasonic Inspection of the Accumulator Screw−Caps It will take an estimated 8.0 man−hours to complete PART B of this service bulletin. The man−hours are divided as shown in the table that follows:

TASK MAN−HOURS MAX. PERSONS ELAPSED TIME
(1) Job Set−Up 1 1 1 (2) Procedure 3 1 3 (3) Test 3 2 1.5 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 7 of 21 Nov 21/2006 Revision D, Dec 22/2010TASK MAN−HOURS MAX. PERSONS ELAPSED TIME
(4) Job Close−Out 1 1 1

G. Material − Price and Availability (1) There are no kits for this service bulletin. (2) Refer to paragraph 3.C. for a list of consumables for this service bulletin. H. Tooling − Price and Availability (1) The tool kit in the table that follows is available from Bombardier. NOTE : For a list of the kit contents, refer to paragraph 3.A.

KIT NUMBER NAME

670BA32021K90 NDT Calibration Tool

NOTE : 601R32

– 103K90 NDT calibration tool can be used as an alternative tool. (2) Please send a purchase order to the address below to schedule the kit: Service Bulletin Kit Support Team 123 Garratt Blvd, N42

– 24 Toronto, Ontario Canada M3K 1Y5 Fax: 416−375−3060 Phone: 416−375−3920 Please contact at the address above for terms and conditions. I. Weight and Balance Not changed.
J. Electrical Load Data Not changed. 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 8 of 21 Nov 21/2006 Revision D, Dec 22/2010K. References − Restriction and/or Special Instruction (RSI), C−32−0954−00, Revision G. − Tactair Service Bulletin SB0860204001−32−02, dated Jan 27, 2010. − Bombardier Regional Jet Series All Operator Message (AOM), No. 614. − Aircraft Maintenance Manual (AMM), CSP B−001. − For Bombardier Aerospace reference only: PCA 72415. − Nondestructive Testing Manual (NDT), CSP B−010.
L. Other Publications Affected None. M. Relationship Chart Not applicable. 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 9 of 21 Nov 21/2006 Revision D, Dec 22/20102. ACCOMPLISHMENT INSTRUCTIONS PART A − Detailed Inspection of the Accumulator Screw−Caps A. Job Set−Up (1) Reference Information

REFERENCE DESIGNATION AMM 12−00−00−867−801 Standard Aircraft Configuration for Maintenance
AMM 12−00−06−862−802 Release Hydraulic Pressure of System No. 1 and No. 2
AMM 12−00−06−862−804 Release Hydraulic Pressure of System No. 3
AMM 12−12−29−614−801 Servicing of the Hydraulic System Accumulators
AMM 24−00−00−861−802 Remove Electrical Power from the Aircraft
AMM 24−00−00−910−801 Electrical/Electronic Safety Precautions
AMM 32−43−16−710−801 Operational Test of the Brake Accumulator
AMM 52−45−56−000−801 Removal of the Hydraulic Access Door (121AL)
AMM 52−45−56−400−801 Installation of the Hydraulic Access Door (121AL) (2) Standard Practices Information

REFERENCE DESIGNATION AMM 51−26−00−110−801 Solvent Cleaning (3) Make sure that the aircraft is in standard configuration for maintenance (AMM 12−00−00−867−801). 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 10 of 21 Nov 21/2006 Revision D, Dec 22/2010(4) Remove the access panel that follows:

PANEL NAME REFERENCE
121AL Removal of the Hydraulic Access Door (121AL) AMM 52−45−56−000−801

(5) Open access door 211AL. WARNING : OBEY ALL THE SAFETY PRECAUTIONS WHEN YOU DO MAINTENANCE ON OR NEAR ELECTRICAL/ELECTRONIC EQUIPMENT. YOU CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT. (6) Obey all the electrical/electronic safety precautions (AMM 24−00−00−910−801). (7) Remove the electrical power from the aircraft (AMM 24−00−00−861−802). WARNING : OBEY ALL HYDRAULIC SAFETY PRECAUTIONS WHEN YOU DO WORK ON THE HYDRAULIC SYSTEM AND HYDRAULIC SYSTEM COMPONENTS. YOU CAN CAUSE INJURY TO PERSONS AND DAMAGE TO THE EQUIPMENT. (8) Release the hydraulic pressure from hydraulic system No. 2 (AMM 12−00−06−862−802). (9) Release the hydraulic pressure from hydraulic system No. 3 (AMM 12−00−06−862−804). (10) Operate the pilot’s or co−pilot’s brake pedals to release the hydraulic pressure from the brake accumulators (approximately six times). (11) Open, safety, and tag the circuit breakers that follow:

CB−PANEL CB NO. NAME CBP−1 F11 HYD SYST AC PUMP CONT 3B CBP−1 F14 HYD SYST AC PUMP CONT 2 CBP−2 F14 HYD SYST AC PUMP CONT 3A ACPC ACPC HYD PUMP 2B ACPC ACPC HYD PUMP 3B 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 11 of 21 Nov 21/2006 Revision D, Dec 22/2010CB−PANEL CB NO. NAME ACPC ACPC HYD PUMP 3A Refer to Figure 1. (12) Release the nitrogen pressure as follows: (a) Remove the dust cap (4) from the nitrogen charge valve (3). (b) Carefully loosen the thin nut on the nitrogen charge valve (3). (c) Let the nitrogen pressure go to zero.
B. Procedure Refer to Figure 1,2. NOTE : This procedure is applicable to the inboard and outboard brake accumulators. The procedure that follows is written for the inboard brake accumulator. The differences are given. WARNING : OBEY ALL CLEANING SAFETY PRECAUTIONS. YOU CAN CAUSE INJURIES TO PERSONS AND DAMAGE TO THE EQUIPMENT. (1) With solvent, clean the tapered section of the accumulator screw−caps with isopropyl alcohol and a dry, clean cloth (AMM 51−26−00−110−801). (2) Do a detailed inspection of the accumulator screw−caps (2 per accumulator) for indications of a crack. (3) If there is a crack on the accumulator do PART B. NOTE : Confirm the crack with an ultrasonic inspection as described in PART B. (4) If there is no crack, do the servicing of the inboard and/or the outboard brake accumulators (1) (AMM 12−12−29−614−801). C. Job Close−Out (1) Remove all tools, equipment, and unwanted materials from the work area. (2) Remove the tags and close the circuit breakers that follow: 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 12 of 21 Nov 21/2006 Revision D, Dec 22/2010CB−PANEL CB NO. NAME CBP−1 F11 HYD SYST AC PUMP CONT 3B CBP−1 F14 HYD SYST AC PUMP CONT 2 CBP−2 F14 HYD SYST AC PUMP CONT 3A ACPC ACPC HYD PUMP 2B ACPC ACPC HYD PUMP 3B ACPC ACPC HYD PUMP 3A (3) Do an operational test of the brake accumulators (AMM 32−43−16−710−801). (4) Install the access panel that follows:

PANEL NAME REFERENCE
121AL Removal of the Hydraulic Access Door (121AL) AMM 52−45−56−400−801

(5) Close access door 211AL. (6) When PART A of this service bulletin is completed, make this entry in the applicable logbook as follows: "Alert Service Bulletin A670BA−32−021, Revision D, Landing Gear − Brake System − Inspection of the Accumulator Screw−Caps (P/N 0860204001), PART A, incorporated." PART B − Ultrasonic Inspection of the Accumulator Screw−Caps A. Job Set−Up (1) Reference Information

REFERENCE DESIGNATION AMM 12−00−00−867−801 Standard Aircraft Configuration for Maintenance
AMM 12−00−06−862−802 Release Hydraulic Pressure of System No. 1 and No. 2 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 13 of 21 Nov 21/2006 Revision D, Dec 22/2010REFERENCE DESIGNATION AMM 12−00−06−862−804 Release Hydraulic Pressure of System No. 3
AMM 12−12−29−614−801 Servicing of the Hydraulic System Accumulators
AMM 24−00−00−861−802 Remove Electrical Power from the Aircraft
AMM 24−00−00−910−801 Electrical/Electronic Safety Precautions
AMM 29−10−00−870−801 Bleed Hydraulic systems No. 1 and No. 2
AMM 29−10−00−870−802 Bleed Hydraulic system No. 3
AMM 32−43−16−000−801 Removal of the Brake Accumulator
AMM 32−43−16−400−801 Installation of the Brake Accumulator
AMM 32−43−16−710−801 Operational Test of the Brake Accumulator
AMM 52−45−56−000−801 Removal of the Hydraulic Access Door (121AL)
AMM 52−45−56−400−801 Installation of the Hydraulic Access Door (121AL) (2) Make sure that the aircraft is in standard configuration for maintenance (AMM 12−00−00−867−801). (3) Remove the access panel that follows:

PANEL NAME REFERENCE
121AL Removal of the Hydraulic Access Door (121AL) AMM 52−45−56−000−801

(4) Open access door 211AL. 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 14 of 21 Nov 21/2006 Revision D, Dec 22/2010WARNING : OBEY ALL THE SAFETY PRECAUTIONS WHEN YOU DO MAINTENANCE ON OR NEAR ELECTRICAL/ELECTRONIC EQUIPMENT. YOU CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT. (5) Obey all the electrical/electronic safety precautions (AMM 24−00−00−910−801). (6) Remove the electrical power from the aircraft (AMM 24−00−00−861−802). WARNING : OBEY ALL HYDRAULIC SAFETY PRECAUTIONS WHEN YOU DO WORK ON THE HYDRAULIC SYSTEM AND HYDRAULIC SYSTEM COMPONENTS. YOU CAN CAUSE INJURY TO PERSONS AND DAMAGE TO THE EQUIPMENT. (7) Release the hydraulic pressure from hydraulic system No. 2 (AMM 12−00−06−862−802). (8) Release the hydraulic pressure from hydraulic system No. 3 (AMM 12−00−06−862−804). (9) Operate the pilot’s or co−pilot’s brake pedals to release the hydraulic pressure from the brake accumulators (approximately six times). (10) Open, safety, and tag the circuit breakers that follow:

CB−PANEL CB NO. NAME CBP−1 F11 HYD SYST AC PUMP CONT 3B CBP−1 F14 HYD SYST AC PUMP CONT 2 CBP−2 F14 HYD SYST AC PUMP CONT 3A ACPC ACPC HYD PUMP 2B ACPC ACPC HYD PUMP 3B ACPC ACPC HYD PUMP 3A Refer to Figure 2. (11) Release the nitrogen pressure as follows: (a) Remove the dust cap (4) from the nitrogen charge valve (3). 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 15 of 21 Nov 21/2006 Revision D, Dec 22/2010(b) Carefully loosen the thin nut on the nitrogen charge valve (3). (c) Let the nitrogen pressure go to zero. (12) Remove the brake accumulators (AMM 32−43−16−000−801).
B. Procedure (1) Do an ultrasonic inspection on the inboard and the outboard brake accumulators (Refer to Appendix A). (2) If there is a crack do as follows: (a) Replace the accumulator(s) (AMM 32−43−16−000−801). (b) Send the accumulator(s) to:
Bombardier CRJ In Service Engineering 13100 Boulevard Henri Fabre, Mirabel Quebec, Canada J7N 3C6 C/O ISE group Dept# 662 (c) Install a new brake accumulator(s) (AMM 32−43−16−400−801). (3) If there is no crack, install the brake accumulators (AMM 32−43−16−400−801). 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 16 of 21 Nov 21/2006 Revision D, Dec 22/2010ba4343a01.cgm, lr, oct11/2006 LEGEND 1. Brake accumulator. 2. Screw cap. 3. Nitrogen charge valve. 4. Dust cap. BRAKE ACCUMULATOR CHARGING POINTS INBOARD BRAKE ACCUMULATOR (SYSTEM NO. 3) 3 4

OUTBOARD BRAKE ACCUMULATOR (SYSTEM NO. 2)

2

1

2 A

A B

B 

### ALERT SERVICE BULLETIN A670BA−32−021

Accumulator Servicing Location Figure 1

S.B. A670BA−32−021 Page 17 of 21 Nov 21/2006 Revision D, Dec 22/2010ba4343a02_01.cgm LEGEND 1. Brake accumulator. 2. Screw cap. A

B 2

1

2

A 1

1

NOTE Inspect the full circumference of the part at the shaded area (typical). 1 B 1 B 

### ALERT SERVICE BULLETIN A670BA−32−021

Accumulator Inspection Location Figure 2

S.B. A670BA−32−021 Page 18 of 21 Nov 21/2006 Revision D, Dec 22/2010C. Job Close−Out (1) Remove all tools, equipment, and unwanted materials from the work area. (2) Remove the tags and close the circuit breakers that follow:

CB−PANEL CB NO. NAME CBP−1 F11 HYD SYST AC PUMP CONT 3B CBP−1 F14 HYD SYST AC PUMP CONT 2 CBP−2 F14 HYD SYST AC PUMP CONT 3A ACPC ACPC HYD PUMP 2B ACPC ACPC HYD PUMP 3B ACPC ACPC HYD PUMP 3A (3) Do the bleeding of No. 2 hydraulic system (AMM 29−10−00−870−801). (4) Do the bleeding of No. 3 hydraulic system (AMM 29−10−00−870−802). (5) Do the operational test of the brake accumulator (AMM 32−43−16−710−801). (6) Install the access panel that follows:

PANEL NAME REFERENCE
121AL Removal of the Hydraulic Access Door (121AL) AMM 52−45−56−400−801

(7) Close access door 211AL. (8) When PART B of this service bulletin is completed, make this entry in the applicable logbook as follows: "Alert Service Bulletin A670BA−32−021, Revision D, Landing Gear − Brake System − Inspection of the Accumulator Screw−Caps (P/N 0860204001), PART B, incorporated." 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 19 of 21 Nov 21/2006 Revision D, Dec 22/20103. MATERIAL INFORMATION A. Kit Information Kit Content:

KIT 670BA32021K90

PART NUMBER QUANTITY NAME ALTERNATE PART(S) NOTES

T11330 1 NDT Calibration Tool [1] Refer to paragraph 1.H. for special terms and conditions.

B. Rotable Information
None. C. Consumable Information The material that follows is necessary to do this service bulletin and can be ordered from Bombardier Aerospace Regional Aircraft or purchased directly from industry sources. If the material is ordered from Bombardier Aerospace Regional Aircraft, there can be some lead time because of shelf life of the material.

CONSUMABLES

SPECIFICATION QUANTITY NAME REFERENCE
MIL−C−85043 As necessary Cloths, cleaning, low lint 05−001 [1]

TT−I−735 As necessary Alcohol, isopropyl 11−004 [1]
[1] Refer to AMM 51−31−00−992−801.

NOTE : To complete this list of consumables, refer to the different tasks given as references in this service bulletin and the Appendix A. 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 20 of 21 Nov 21/2006 Revision D, Dec 22/2010D. Special Tools and Equipment For a list of special tools and equipment, refer to the different tasks given as references in this service bulletin. E. Disposition of Parts Not applicable. 

### ALERT SERVICE BULLETIN A670BA−32−021

S.B. A670BA−32−021 Page 21 of 21 Nov 21/2006 Revision D, Dec 22/2010Nov 21/2006 S.B A670BA-32-021 Revision A, Oct 18/2007 APPENDIX A Page A1 of A9 

# Alert Service Bulletin A670BA-32-021 Landing Gear - Brake System - Inspection of the Accumulator Screw-Caps (P/N 0860204001)

The Repair Non Incorporated Order contain ed in this appendix are referenced in the ACCOMPLISHEMENT INSTRUCTION of Service Bulletin A670BA-32-021

### ALERT SERVICE BULLETIN A670BA-32-021

Nov 21/2006 S.B A670BA-32-021 Revision A, Oct 18/2007 APPENDIX A Page A2 of A9 Ultrasonic Inspection of the Accumulator Screw-Caps
1. General
A. Function Refer to Figure 1 . This inspection procedure is used to det ect subsurface cracks at the internal shoulder of the Screw Caps (Gas and Fluid ends, item 2) of the Brake Accumulator System No. 2 and No. 3 (1).
B. Reference Information For additional data that is necessary to do this inspection, refer to manuals that follow: - Nondestructive Testing Manual (NDT M CSP B-010) Part 1, 51-20-004-270- A01, General Information. - Structural Repair Manual (SRM) - Aircraft Maintenance Manual (AMM)
C. Location The inspection area is in Zone 120 (Refer to AMM 06- 20-00-992-801-AA1). D. Parts Examined in this procedure

DESCRIPTION PART NUMBER VENDOR PART NUMBER MATERIAL
Brake Accumulator Screw Cap 0860204001 7075-T73 Al Alloy

### ALERT SERVICE BULLETIN A670BA-32-021

Nov 21/2006 S.B A670BA-32-021 Revision A, Oct 18/2007 APPENDIX A Page A3 of A9 2. Tools and Equipment Refer to Figure 2 .
A. Use the items that follo w, or their equivalent (Ref er to the NDTM Part 1, 51- 20-004-270-A01). NOTE: Equivalent ultrasoni c equipment can be used pr ovided that it satisfies the requirements of this procedure and is capable of resolving the reference notch(es) in the calibration reference standard (CRS) at the required level of sensitivity.
- Ultrasonic flaw detecto r, Sonatest Model: UFDS - Potted angle beam contact transduc er, 70 degrees refractive angle in aluminum, 5.0 MHz frequency, contact surf ace 0.32-inch (8.13 mm) by 0.70-inch (17.78 mm) UTX Model: CX-118 - Microdot to BNC type coaxial cable.
- Tactair Calibration Reference Standar d: T11330, similar in geometry as the part to be inspected containing several electrical discharge machined (EDM) notches (Figure 2 ). - Inspectech LTD: Gorptech I ndustrial Ultrasonic Couplant Gel. B. Location 3. Inspection for Subsurface Cracks on th e Screw Cap Inner Shoulder of the Accumulator A. Cleaning Refer to Figure 1.
WARNING: OBEY ALL THE SAFETY PRECAUTIONS WHEN YOU USE CHLORINATED OR OTHER SOLVENTS TO CLEAN THE WORK SURFACES. MAKE SURE THAT THERE IS A SUFFICI ENT SUPPLY OF FRESH AIR. USE PROTECTIVE CLOTHING AND SAFETY GL ASSES. IF THIS IS NOT DONE, INJURIES TO PERSONS CAN OCCUR. (1) With solvent, clean the entire (360 degrees around) tapered section of the screw caps where the transducer is to make contact during the inspection. Refer to AMM 51-26-00-110-801. Refer to Figure 1.

### ALERT SERVICE BULLETIN A670BA-32-021

Nov 21/2006 S.B A670BA-32-021 Revision A, Oct 18/2007 APPENDIX A Page A4 of A9 B. Equipment Calibration

NOTE: Make sure that you follow t he manufacturer's instructions when operating the test equipment.
NOTE: Do not allow the ultr asonic couplant to dry on t he inspection surface. If necessary, add more couplant, to replenish the surface. Refer to Figure 2 ,Figure 3 . (1) Attach the 70° angle beam transducer to coaxial cable and connect the cable to the ultrasonic instrument. (2) Turn on the power and set the ultras onic instrument to pulse-echo test mode and 5 MHz test frequency. (3) Apply couplant to tapered section of the calibration reference standard (CRS) T11330. (4) Place the transducer firmly to the tapered section on the CRS such that sound beam is directed towards the in ternal shoulder of the screw cap. (5) Manipulate the transducer to obtain a maximized amplitude signal from EDM notch A (NA) and adjust the instrument GAIN control to set the signal at 80% full screen height (FSH). (6) Adjust and position the leading edge of the notch signal at 50% of the horizontal baseline an d the signal from the external shoulder at approximately 75% of the horiz ontal baseline.

### ALERT SERVICE BULLETIN A670BA-32-021

Nov 21/2006 S.B A670BA-32-021 Revision A, Oct 18/2007 APPENDIX A Page A5 of A9 C. Inspection Procedure Refer to Figure 1 , Figure 2 , Figure 4 . (1) After calibration as outlined in secti on 3.B., apply an even la yer of couplant to the tapered section on the brake accu mulator screw cap (2 caps per accumulators) to be inspected. (2) Place the transducer firml y to the tapered section of the Screw Cap such that the sound beam is towards to internal shoulder. (3) Manipulate the transducer towards and aw ay from the shoulder with a slight swiveling motion. (4) Inspect 360 degrees around the cap for cracks.

D. Evaluation of Indications (1) Any indication with an amplitude si gnal of 60% FSH or greater at approximately 50% of the horizontal baseline limit is considered a suspect indication and is cause for further evaluation. (2) Verify and ensure the indication is not from the external shoulder i.e. the transducer moved too forward to the edge of the external shoulder or the baseline has shifted accidentally. (2) If the indication is a crack, determi ne the approximate length of crack by scanning in both directions from the peak signal until the signal has dropped to 40% FSH and mark the center point of the transducer. The circumferential crack length is the distanc e between the two points. E. Acceptance or Rejection Criteria: (1) All distinct indications with an am plitude signal of 60% FSH or greater appearing at approximately 50% of the horizontal base line is classified as a crack indication and is caused for rejection. (3) Record results.

4. Close-out
A. Refer to the Close-Out section of Alert Service Bulletin A670BA-32-021 B. PART B.

### ALERT SERVICE BULLETIN A670BA-32-021

Nov 21/2006 S.B A670BA-32-021 Revision A, Oct 18/2007 APPENDIX A Page A6 of A9ba4343a02.cgm, lr, oct11/2006 LEGEND 1. Brake accumulator. 2. Screw cap. 2

1

2

NOTE Inspect the full circumference of the part at the shaded area (typical). 1 A

A 1 TYPICAL 1

1

B B

Brake Accumulator Screw Cap Locations Figure 1

### ALERT SERVICE BULLETIN A670BA-32-021

Nov 21/2006 S.B A670BA-32-021 Revision A, Oct 18/2007 APPENDIX A Page A7 of A9ba4396a01.cgm, lr, oct12/2006
0.050 in. (1.27 mm) DP
NOTCH B 0.075 in. (1.90 mm) BOTH SIDES

NOTCH A NOTCH C 0.050 in. (1.27 mm) BOTH SIDES

0.050 in. (1.27 mm) DP 0.050 in. (1.27 mm) DP

0.100 in. (2.54 mm) BOTH SIDES 45 DEGREE

45 DEGREE C D

E

C D E A A B

B A A

B B

Tactair CRS Number T11330 Figure 2

### ALERT SERVICE BULLETIN A670BA-32-021

Nov 21/2006 S.B A670BA-32-021 Revision A, Oct 18/2007 APPENDIX A Page A8 of A9ba4397a01.cgm, lr, oct12/2006 TRANSDUCER PLACEMENT EXTERNAL SHOULDER

INTERNAL SHOULDER

TRANSDUCER PLACEMENT EXTERNAL SHOULDER

EDM NOTCH A 0.050 in. DP X 0.100 in. LG (1.27 mm DP X 2.54 mm LG) 100%

50%

0 50 100 IP

EES

100%

50%

0 50 100 IP

EES ENA CRT DISPLAY - CRACK-FREE SCREW C A

CRT DISPLAY OF CRACK SCREW CAP

LEGEND IP. Initial pulse. EES. Echo from external shoulder (non relevant). ENA. Echo from notch A (0.050 in. DP X 0.100 in. LG (1.27 mm DP X 2.54 mm LG)) or typical crack indication.

### ALERT SERVICE BULLETIN A670BA-32-021

Nov 21/2006 S.B A670BA-32-021 Revision A, Oct 18/2007 APPENDIX A Page A9 of A9 CRT Display Calibration and Familiarization Figure 3ba4398a01.cgm, lr, oct12/2006 EXTERNAL SHOULDER

POTENTIAL CRACK AT INTERNAL SHOULDER

TRANSDUCER PLACEMENT AND SCANNING MOVEMENT

Transducer placement Figure 4THANK YOU FOR ANSWERING THIS EVALUATION FORM UPON COMPLETION OF THIS EVALUATION FORM/COMPLIANCE SHEET, FAX TO 450-476-7300 

### SERVICE BULLETIN EVALUATI ON FORM/COMPLIANCE SHEET (YOUR IDEAS WILL HELP US PROVIDE BETTER BULLETINS)

SERVICE BULLETIN : 670BA- 32 -0 21 ISSUE: D

STRONGLY DISAGREE NEUTRAL AGREE STRONGLY DISAGREE AGREE

• Instructions to do the Service Bulletin were accurate. Comments: 

##     

• Illustration(s), figure(s), picture(s) and/or kit drawing(s) were helpful to carry out instructions. Comments: 

##     

• If a parts kit was required, did the kit contents received agree with the contents listed in the bulletin? Comments: 

##     

• Aircraft hands-on work was accomplished in estimated time. Comments: 

##     

• Overall, I was satisfied with this Service Bulletin. Comments: 

##     

PLEASE SUPPLY US WITH THE FOLLOWING DATA AND FAX TO (450) 476-7300:

OPERATOR: NAME (Please print)
SERVICE CENTER: TELEPHONE:
AIRCRAFT SERIAL NO.: FACSIMILE:
DATE OF SB INCORPOARTION