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 SHEET
Landing 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 22/2010
D. 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 22/2010
APPLICABLE 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 22/2010
APPLICABLE 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 22/2010
NOTE: 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 22/2010
TASK 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 22/2010
K. 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 22/2010
2. 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

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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

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Nov 21/2006

Revision D, Dec 22/2010
CB−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

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Revision D, Dec 22/2010
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 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

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Nov 21/2006

Revision D, Dec 22/2010
REFERENCE 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

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Nov 21/2006

Revision D, Dec 22/2010
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.

(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

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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

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Page 16 of 21

Nov 21/2006

Revision D, Dec 22/2010
ba4343a01.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 22/2010
ba4343a02_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

B 1

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 22/2010
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:

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 22/2010
3. 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 22/2010
D. 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 22/2010
 

Nov 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 contained 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 detect 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 (NDTM 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 follow, or their equivalent (Refer to the NDTM Part 1, 51-

20-004-270-A01). 

NOTE: Equivalent ultrasonic equipment can be used provided 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 detector, Sonatest Model: UFDS 

- Potted angle beam contact transducer, 70 degrees refractive angle in 

aluminum, 5.0 MHz frequency, contact surface 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 Standard: T11330, similar in geometry as the 

part to be inspected containing several electrical discharge machined (EDM) 

notches (Figure 2 ). 

- Inspectech LTD: Gorptech Industrial Ultrasonic Couplant Gel. 

B. Location 

3. Inspection for Subsurface Cracks on the 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 SUFFICIENT SUPPLY OF FRESH AIR. USE 

PROTECTIVE CLOTHING AND SAFETY GLASSES. 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 the manufacturer's instructions when 

operating the test equipment. 

NOTE: Do not allow the ultrasonic couplant to dry on the 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 ultrasonic 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 internal 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 and the signal from the external shoulder at approximately 

75% of the horizontal 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 section 3.B., apply an even layer of couplant to 

the tapered section on the brake accumulator screw cap (2 caps per 

accumulators) to be inspected. 

(2) Place the transducer firmly to the tapered section of the Screw Cap such that 

the sound beam is towards to internal shoulder. 

(3) Manipulate the transducer towards and away 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 signal 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, determine 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 distance between the two points. 

E. Acceptance or Rejection Criteria: 

(1) All distinct indications with an amplitude signal of 60% FSH or greater 

appearing at approximately 50% of the horizontal baseline 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 CA

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 3 

ba4398a01.cgm, lr, oct12/2006

EXTERNAL

SHOULDER

POTENTIAL CRACK

AT INTERNAL

SHOULDER

TRANSDUCER

PLACEMENT AND

SCANNING MOVEMENT

Transducer placement 

Figure 4 
THANK YOU FOR ANSWERING THIS EVALUATION FORM 

UPON COMPLETION OF THIS EVALUATION FORM/COMPLIANCE SHEET, FAX TO 

450-476-7300 

SERVICE BULLETIN EVALUATION FORM/COMPLIANCE SHEET 

(YOUR IDEAS WILL HELP US PROVIDE BETTER BULLETINS) 

SERVICE BULLETIN : 670BA-32-021 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