# Bombardier Service Bulletin 100-53-35

Copy: No revision named ("100-53-35"), 13 pages: PDF https://openairdocs.org/files/sha256/b9/66/b966cb0947d00c7ee1ab57a4a6654c96fe0c5b0e00d2722f0dd8a4cfa67919fb; text https://openairdocs.org/service-documents/bombardier/sb-100-53-35/file/b966cb0947d0.md. Rights: © Bombardier Inc. Filed by the FAA in regulations.gov docket FAA-2022-1480; AD 2023-03-18 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication.

## Details

- Manufacturer: [Bombardier](https://openairdocs.org/service-documents/bombardier.md)
- Type: Service bulletin (Service Bulletin)
- Number: 100-53-35
- Page: https://openairdocs.org/service-documents/bombardier/sb-100-53-35

## ADs that cite it (1) (OpenAirDocs)

Newest first, with the revision each names, as OpenAirDocs read it from the AD's text.

- [AD 2023-03-18](https://openairdocs.org/ad/2023-03-18.md), effective Apr 4, 2023: No revision named

Also cited in [1 proposed AD](https://openairdocs.org/service-documents/bombardier/sb-100-53-35/proposed.md).

## Text (13 pages)

Rights: © Bombardier Inc. Filed by the FAA in regulations.gov docket FAA-2022-1480; AD 2023-03-18 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. Each page's text from the PDF; open the PDF at a page with #page=N.

### Page 1

SPECIAL CHECK/REWORK - FUSELAGE - REPLACEMENT OF THE AUXILIARY
POWER UNIT (APU) MUFFLER ELECTRICAL BONDING STRAP
The information below is provided for your reference. For full details, including labor and part
coverage, please see corresponding paragraph contained within this bulletin.
RECOMMENDED
SPECIFIED TIME COMPLIANCE
COMPLIANCE TIME
Refer to Paragraph 1.D.
EFFECTIVITY: A/C Serial No. 20003 to 20500
MANPOWER: Refer to Paragraph 1.F.
CONTINUED AIRWORTHINESS (CAW)
FLEET CAMPAIGN YES NO
TLMC, CH 5 AFFECTED NOYES
KITS and/or PARTS YES NO
TOOLING/GSE YES NO
PLANNING INFORMATION NOYES
DEDICATED SCHEDULE NOYES
PREREQUISITE SERVICE BULLETINS: N/A
NOTE: This Service Bulletin may be subject to an Airworthiness Directive which will make
it necessary to implement this Service Bulletin.
To place an order for parts or kits, please call Bombardier Aviation Parts Services at:
514−855−2999 or 1−866−538−1247
SERVICE BULLETIN SUMMARY
my.businessaircraft.bombardier.com
MODEL BD−100−1A10 (CH−300)
ATA 53−00
FUSELAGE
Basic Issue: Dec 06/2021 100−53−35
Page 1 of 1
This Service Bulletin is available at:

### Page 2

SPECIAL CHECK/REWORK - FUSELAGE - REPLACEMENT OF THE AUXILIARY
POWER UNIT (APU) MUFFLER ELECTRICAL BONDING STRAP
1. PLANNING INFORMATION
NOTES:1 . Before you do this Service Bulletin, examine all STC, STA or
equivalent action changes to make sure that this Service Bulletin can
be completed.
A. Effectivity
BD−100−1A10 aircraft, Serial No. 20003 to 20500.
NOTE: The instructions given 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 Aviation Service Bulletin(s).
B. Reason
A few aircraft have been found to have cracks in the tailcone upper firewall where
the APU muffler electrical bonding strap is attached. This can possibly cause a
breach of the firewall, reduced lightning strike protection and increased radio
interference.
This Service Bulletin introduces a special check/rework to replace the rigid
electrical bonding strap with a flexible jumper cable assembly. The benefits to the
operator are improved reliability/dispatchability/cost avoidance.
C. Description
This Service Bulletin gives instructions in PART A, to:
− Inspect the tailcone upper firewall for cracks or other defects, and
− If necessary, repair the tailcone upper firewall.
SERVICE BULLETIN
my.businessaircraft.bombardier.com
MODEL BD−100−1A10 (CH−300)
ATA 53−00
FUSELAGE
Refer to applicable governmental agency regulations and requirements and make sure that the work described in this
Service Bulletin is performed in compliance with manufacturer’s recommendations and/or acceptable industry standards.
This document is proprietary to Bombardier Inc. and/or its affiliates and may not be reproduced or copied in any form or
by any means without the prior written consent of Bombardier Inc. and/or its affiliates.
 2021 Bombardier Inc.  All rights reserved
Learjet, Challenger, Global, are registered trademarks of Bombardier Inc. or its subsidiaries.
Basic Issue: Dec 06/2021 100−53−35
Page 1 of 10
This Service Bulletin is available at:

### Page 3

This Service Bulletin gives instructions in PART B, to:
− Remove the APU electrical bonding strap,
− Install the new flexible APU muffler jumper cable assembly, and
− Do the necessary tests to make sure that the system operates correctly.
This Service Bulletin gives instructions in PART C, to:
− Do the necessary repairs if cracks or other defects are found at the tailcone
upper firewall,
− Install the new flexible APU muffler jumper cable assembly, and
− Do the necessary tests to make sure that the system operates correctly.
D. Compliance
Recommended within 48 months of this Service Bulletin release date (Basic Issue).
NOTE: If it is not possible to complete all the instructions in this Service Bulletin
because of the aircraft configuration, submit an SRPSA for analysis and to
get an approved disposition to complete this Service Bulletin.Standard
SRPSA fees may apply. Refer to the Services section of the Bombardier
customer portal for the latest prices, rates and fees.
E. Approval
The technical content of this Service Bulletin has been approved under the
authority of Transport Canada Civil Aviation (TCCA) Design Approval Organization
(DAO) No. DAO #93−Q−02.
NOTES: 1. The technical content of this Service Bulletin is accepted by the FAA
under the Canada/USA bilateral Aviation Safety Agreement.
2. The technical content of this Service Bulletin is accepted by EASA
under the Canada/EU bilateral Aviation Safety Agreement.
MODEL BD−100−1A10 (CH−300)
Basic Issue: Dec 06/2021 100−53−35
Page 2 of 10

### Page 4

F. Manpower
NOTES: 1. The man−hours given are to help you schedule the tasks given in this
Service Bulletin. The man−hours are for direct labor performed by an
experienced crew and do not include the time for familiarization,
planning, aircraft preparation in hangar such as towing and
positioning of scaffolds, removal of interior furnishings, repainting,
supervision and inspection.
For more information related to the manpower, refer to SB
100−00−02.
2. This Service Bulletin may require consumable materials that have
specific curing times (refer to Paragraph 3). The accumulated curing
time is not included in the man−hours and should be considered for
planning purposes before you schedule this Service Bulletin.
3. Labor hours are based on the fact that this Special Check/Rework will
be done at the next scheduled maintenance task or inspection (e.g.
48 month or 96 month inspection, etc.). Therefore no man−hours are
allotted to prepare the aircraft for maintenance or to prepare for this
Service Bulletin.
Up to 1 man−hour is necessary to do Part A and Part B of this Special
Check/Rework.
Up to 24 man−hours are necessary to do Part C of this Special Check/Rework.
Bombardier Aviation does not pay for the labor to perform this Recommended
Service Bulletin at any time.
G. Material − Cost and Availability
KIT NO. PRICE
100K53−35
Please contact Bombardier Aviation
Parts Services, in Montreal, for delivery
lead times and confirmation of prices.
Bombardier Aviation does not pay for the kit for this Recommended Service Bulletin
at any time.
For all parts transactions, Bombardier Aviation’s current Spare Parts and
Component Repair Price Catalogue General Terms and Conditions apply. These
terms and conditions are found on the Bombardier Customer Portal at:
my.businessaircraft.bombardier.com
Smart Parts Plus does not pay for the kits.
MODEL BD−100−1A10 (CH−300)
Basic Issue: Dec 06/2021 100−53−35
Page 3 of 10

### Page 5

H. Tooling
The equipment and tools listed below are necessary to do this Special
Check/Rework:
GSE REFERENCE NO. PART NO. DESCRIPTION
20X−00−04 M1−G−Kit Portable Bonding Tester
24−00−24 S4933959−501 Tag, Circuit Breaker
49C−00−01 (for PART C) − APU Fishpole Hoist
49C−00−02 (for PART C) − Protective Sleeve
49C−00−03 (for PART C) − APU Stand and Adapter
Commercially Available − Flashlight
Commercially Available − Magnifying Glass (10xminimum)
Commercially Available − Torque, Wrench 150 to200 lbf in (15 to 25 Nm)
NOTES: 1. Refer to the BD−100 Illustrated Tool and Equipment Manual (ITEM) to
make sure that you use the correct equipment configuration.
2. Refer to the Liability Statement in the ITEM for acceptable GSE
equivalents.
I. Weight and Balance
No change.
J. Electrical Load Data
No change.
K. References
− Bombardier Aviation, Modification Summary BB100T011103, Rev. B.
− Bombardier Aviation, Kit Drawing K1000070318, Rev. −−.
− CH 300 Aircraft Maintenance Manual (AMM), Chapters 6, 10, 24, 28, 49 and 52.
− CH 300 Structural Repair Manual (SRM), Chapter 51 and 53.
− Bombardier Aerospace, SB 100−00−02, Service Bulletin Description and Policy.
− TCCA Airworthiness Directive (pending)
MODEL BD−100−1A10 (CH−300)
Basic Issue: Dec 06/2021 100−53−35
Page 4 of 10

### Page 6

L. Other Publications Affected
− CH 300 Aircraft Illustrated Parts Catalog (AIPC), Chapter 49.
M. Equivalent Service Bulletins
For the Challenger 350 aircraft, use SB 350−53−004.
2. ACCOMPLISHMENT INSTRUCTIONS
NOTE: All references made to zones, access panels and/or doors, are from the
CH 300 AMM, Chapter 6.
A. Aircraft Setup
(1) Obey all electrical/electronic safety precautions. Refer to
AMM 24−00−00−910−801.
(2) Open and tag the circuit breakers that follow:
CB PANEL CB NO. NAME ZONE
LCBP B8 APU PRI 211
RCBP B8 APU SEC 212
(3) Remove the APU access panel (320AB). Refer to AMM 52−43−01−000−801.
(4) Remove the APU left access panel (320BL). Refer to
AMM 52−43−09−000−801.
B. PART A − Special Check − Inspection of the Tail Cone Upper Firewall
NOTE: If it is not possible to complete all the instructions in this Service Bulletin
because of the configuration of the aircraft, submit an SRPSA for analysis
and to get an approved disposition to complete this Service Bulletin
(1) With a flashlight and a magnifying glass (10x, minimum), do a detailed visual
inspection of the upper firewall for cracks and any other defects especially
around the APU muffler electrical bonding strap clip. Make sure that the
lighting and magnification is sufficient to see even the smallest cracks or
defects. Refer to Kit Drawing K1000070318.
(a) If no cracks or other defects are found, do PART B of this Service Bulletin.
(b) If cracks or other defects are found, do Part C of this Service Bulletin.
C. PART B − Rework − Installation of the Flexible Jumper Cable Assembly
(1) Remove and discard nut Part No. MS21043−6, spring washer Part No.
MS35338−160 and washer Part No. NAS1587−6 from the APU exhaust
muffler.
MODEL BD−100−1A10 (CH−300)
Basic Issue: Dec 06/2021 100−53−35
Page 5 of 10

### Page 7

(2) Remove and discard the nut Part No. MS21043−6, spring washer Part No.
MS35338−160, washer Part No. NAS1587−6, bolt Part No. AS21715 and
bonding strap Part No. 1004984050 from the upper firewall clip.
(3) Install the jumper cable assembly Part No. M83413/8−H012NN on the upper
firewall clip as follows:
(a) Install screw Part No. MS35207−311, two washers Part No.
NAS1149D0632J, spring washer Part No. MS35338−46 and nut Part No.
MS35650−3382. Torque the nut 160 to 190 lbf in (18.08 to 21.46 Nm).
(b) Install the jumper cable assembly Part No. M83413/8−H012NN, washer
Part No. NAS1149D0632J, spring washer Part No. MS35338−46 and nut
Part No. MS35650−3382. Torque the nut 160 to 190 lbf in (18.08 to
21.46 Nm).
(4) Attach the jumper cable assembly to the APU exhaust muffler with washer Part
No. NAS1587−6, spring washer Part No. MS35338−160 and nut Part No.
MS21043−6. Torque the nut 160 to 190 lbf in (18.08 to 21.46 Nm).
(5) Do the electrical bonding test of the APU muffler between the APU muffler and
the upper firewall. Refer to SPMM51−80−00−760−801.
NOTE: Make sure that the resistance value is not more than 0.010 ohm.
D. PART C − Repair − Repair of the Tail Cone Upper Firewall
(1) If any cracks are found around the APU muffler electrical bonding strap clip in
PART A, Inspection, before you do PART B, submit an SRPSA with
photographs for repair disposition by email to:
SRPSA@aero.bombardier.com
(2) If any other defects are found in the upper firewall in Part A, Inspection, before
you do Part B, contact Bombardier Aircraft, Customer Support for repair
disposition.
(3) Remove the APU. Refer to AMM 52−43−09−000−801.
(4) When all the repairs have been completed, do PART B of this Service Bulletin.
(5) Install the APU. Refer to AMM 52−43−09−400−801.
E. Close−out
(1) Close the circuit breakers that follow:
CB PANEL CB NO. NAME ZONE
LCBP B8 APU PRI 211
RCBP B8 APU SEC 212
(2) Install the APU left access panel (320BL). Refer to AMM 52−43−09−400−801.
(3) Install the APU access panel (320AB). Refer to AMM 52−43−01−400−801.
MODEL BD−100−1A10 (CH−300)
Basic Issue: Dec 06/2021 100−53−35
Page 6 of 10

### Page 8

(4) Remove all tools, equipment and unwanted materials from the aircraft.
F. Recording
When this Service Bulletin is completed, make an entry in the aircraft log and send
the attached Incorporation Notice to Bombardier Business Aircraft Customer
Services (BBACS).
For information, correction(s), comments(s) and/or feedback regarding Service
Bulletins released on the Customer Portal, please contact the Service Bulletin
Group at the following email address:
bbad_SBgroup@aero.bombardier.com
3. MATERIAL INFORMATION
A. Kits
Kit 100K53−35 is necessary to do PART B and contains the parts that follow:
NEW PART NO. QTY ITEM USED PARTNO. INSTRUCTIONS- DISPOSITION
M83413/
8−H012NN 1
Jumper
Cable
Assembly
1004984050 Discard
MS21043−6 1 Nut, SelfLocking MS21043−6 Discard
MS35207−311 1
Screw,
Machine,
Pan Head
AS21715 Discard
MS35338−46 2 Washer,Spring MS35338−160 Discard
MS35338−160 1 Washer,Spring MS35338−160 Discard
MS35650−3382 2 Nut, Hex MS21043−6 Discard
NAS1587−6 1 Washer NAS1587−6 Discard
MODEL BD−100−1A10 (CH−300)
Basic Issue: Dec 06/2021 100−53−35
Page 7 of 10

### Page 9

NEW PART NO. QTY ITEM USED PARTNO. INSTRUCTIONS- DISPOSITION
NAS1149D0632J 3 Washer, Flat NAS1587−6 Discard
NOTES: 1. In case of discrepancy between this list and the Service Bulletin Kit
Parts List contained in the respective kit, then the later list prevails.
2. The actual quantity for some of the hardware contained in the kit can
be greater than the amount shown in the table as these items are
supplied in prepackaged quantities.
B. Parts
No parts required.
C. Material
No materials required.
D. Publications
No publications required.
MODEL BD−100−1A10 (CH−300)
Basic Issue: Dec 06/2021 100−53−35
Page 8 of 10

### Page 10

SB350−53−004−70318−NC−S1−PL 
MODEL BD−100−1A10 (CH−300)
PL K1000070318 − Kit − Bonding Jumper Upgrade, APU Muffler
(Sheet 1 of 1, Rev. )
Basic Issue: Dec 06/2021 100−53−35
Page 9 of 10

### Page 11

SB350−53−004−70318−NC−S1 
Kit − Bonding Jumper Upgrade, APU Muffler
Basic Issue: Dec 06/2021 100−53−35
Page 10 of 10

### Page 12

100−53−35 Basic Dec 06/2021
SPECIAL CHECK/REWORK − FUSELAGE − REPLACEMENT OF THE
AUXILIARY POWER UNIT (APU) MUFFLER ELECTRICAL BONDING
STRAP
bbad_SBgroup@aero.bombardier.com
NOTE: Please use Salesforce only for troubleshooting issues or when Engineering
deviation is necessary to accomplish the Service Bulletin modification.
SERVICE BULLETIN EVALUATION FORM
(Your ideas will help us provide better bulletins)
SERVICE BULLETIN: ISSUE: DATED:
TITLE:
For any information, correction(s), comment(s) and/or feedback regarding Service
Bulletins released on the Customer Portal, please contact the Service Bulletin Group
at the following email address:

### Page 13

SERVICE BULLETIN INCORPORATION SHEET − "100−53−35"
Upon completion of the Service Bulletin, please fill−in, fax to
(514) 855−8798 or e−mail to Fracas at fracas.montreal@aero.bombardier.com
If you’re reporting Service Bulletin (SB) Incorporations to CAMP, sending
this Incorporation Sheet to Bombardier is not mandatory. If your aircraft is
on another tracking system, please contact Bombardier to make arrangements
for automated data submission.
100−53−35 Basic
COMPLIED WITH
YES    NO    N/A
PART A
PART B
PART C
Actual hours to accomplish Service Bulletin:
* NOTES:
Aircraft Serial No. Aircraft Reg. No.
Airframe Hours: Airframe Landings
S.B. Incorporation Date Service Order No.
Facility incorporating S.B.
Name Signature Date
BOMBARDIER
SUBMISSION
Service Bulletin
Number
Rev. * Parts
Completed
Remarks/Reason
(Mandatory if N/A)
1. Where the Service Bulletin is divided into a number of parts (e.g., PARTS A,
B, C, D, etc.) which can be carried out separately, indicate only those parts
completed at this time.
2. For repetitive checks (usually PART A) only the initial check should be
reported unless otherwise stated in the Service Bulletin.
3. When more than one part is carried out at the same time, each part should
be reported.
4. Fill in ’Remark/Reason’ to explain compliance method when N/A is selected.(E.g. Part
not installed, N/A by effectivity, N/A by Part Serial Number, etc.
5. PCW means ’Previously Complied With’.
(dd/mm/yy)
Signature not required if sent by E−Mail (dd/mm/yy)

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