# Bombardier Service Bulletin 84-28-07

Copy: No revision named ("U.S. DOT/FAA - Service Bulletin - 84-28-07"), 12 pages: PDF https://openairdocs.org/files/sha256/94/0f/940fe3bd1114f52a8db417ff43c9679e24ff7bf73fea3105547d0e2a464ce32e; text https://openairdocs.org/service-documents/bombardier/sb-84-28-07/file/940fe3bd1114.md. Rights: © Bombardier Inc. Filed by the FAA in regulations.gov docket FAA-2011-0036; AD 2011-13-06 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: 84-28-07
- Page: https://openairdocs.org/service-documents/bombardier/sb-84-28-07

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

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

- [AD 2011-13-06](https://openairdocs.org/ad/2011-13-06.md), effective Aug 1, 2011: No revision named

## Text (12 pages)

Rights: © Bombardier Inc. Filed by the FAA in regulations.gov docket FAA-2011-0036; AD 2011-13-06 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

D
S . B . 8 4 --- 2 8 --- 0 7
Page 1 of 12
01 Aug 2008
L.S
SERVICE BULLETIN
Customer
Support
ATA SYSTEM: 2800 NUMBER: 84- - -28- - -07
BOMBARDIER AEROSPACE REGIONAL AIRCRAFT CONSIDER THIS
SERVICE BULLETIN TO BE PARTICULARL Y SIGNIFICANT AND
URGES OPERATORS TO PROMPTL Y EVALUATE THE CONTENTS
SUBJECT : Fuel - - - Fuel Indication - - - High Level Sensor - - - Application of Sealant
to exposed end of Sensor T erminal Block Screws - - - Special
Inspection and Rectification - - - ModSum 4- - - 113580
1. PLANNING INFORMA TION
A. Effectivity
Aircraft Affected:
In- - -Service: DHC- - -8 Aircraft Models 401 and 402 Serial Numbers 4119
thru 4205.
Production: ModSum 4- - -113580 is not applicable to aircraft in production.
NOTE: The instructions in this Service Bulletin are only applicable to the systems
and parts installed at the time of delivery on the aircraft or as changed by
Bombardier Aerospace Service Bulletin(s). Before you do this bulletin,
examine all STC or equivalent action changes to make sure this bulletin
can be completed.
Spares Affected:
None

### Page 2

S E R V I C E B U L L E T I N 8 4 --- 2 8 --- 0 7
S . B . 8 4 --- 2 8 --- 0 7
Page 2 of 12
01 Aug 2008
L.S
B. Reason
Problem: This service bulletin (ModSum 4- - -113580) is issued as a result of FAA
certification requirements conveyed by Special Federal Aviation
Regulation 88 (SFAR 88). The regulations are set to enhance fuel tank
system safety.
During inspection of a production aircraft, it was discovered that a layer
of sealant was not applied to completely cover (dome seal) the exposed
threaded end of each of the 3 terminal block screws (part of the high
level sensor) per production requirements.
Solution: This service bulletin conveys a special inspection and rectification
procedure required to make sure affected aircraft are compliant with
production build and SFAR 88 requirements.
The special inspection part of this service bulletin is accomplished to
determine if the exposed threaded end of each terminal block screw
is/was dome sealed during production build.
The rectification part of this service bulletin conveys ModSum
4- - -113580. The ModSum permits application of sealant to completely
cover (dome seal) the exposed threaded end of each terminal block
screw that was missed during the production build.
ModSum 4- - -113580 is designed to enhance fuel tank system safety and
meet FAA SFAR 88 certification requirements.
C. Description
The procedures in this service bulletin give the instructions to do the tasks that
follow:
- - - lock pins are installed thru each main gear and main gear door mechanism
- - - the nose gear ground lock is engaged
- - - the fuel tanks are pressure defueled
- - - all aircraft electrical power is selected to OFF
- - - work platforms or ladders are set up around the wings
- - - certain left and/or right outer wing panels are removed
- - - fuel tanks are vented
- - - the exposed end of each high level sensor terminal block screw is dome sealed
- - - certain left and/or right outer wing panels are installed
- - - the fuel tanks are refueled
- - - log book entries are made

### Page 3

S E R V I C E B U L L E T I N 8 4 --- 2 8 --- 0 7
S . B . 8 4 --- 2 8 --- 0 7
Page 3 of 12
01 Aug 2008
L.S
D. Compliance
Bombardier Inc. recommends incorpora tion of ModSum 4- - -113580 at the earliest
opportunity unless otherwise directed by the operator’s airworthiness authority.
E. Approval
The technical content of this Service Bulletin has been approved under the
authority of the Transport Canada Civil Aviation (TCCA) Design Approval
O r g a n i z a t i o n N o : D A O # 9 3 --- Q --- 0 2 .
F. M a n p o w e r
It will take an estimated 6 man- - -hours to complete this Service Bulletin. The
breakdown of the man- - -hours is shown in the table that follows:
TASK M A N --- H O U R S
J o b S e t --- U p 2.50*
Procedure 1.00
T e s t/R T S NA
Close- - -Out 2.50**
* time required to defuel and vent fuel tank not included
** cure time for sealant not included.
G. Material - - - Price and Availability
This service bulletin is self- - -contained (illustrated). A drawing kit is not required to
accomplish this service bulletin.
H. T ooling - - - Price and Availability
None
I. Weight and Balance
None
J. Electrical Load Data
Not affected

### Page 4

S E R V I C E B U L L E T I N 8 4 --- 2 8 --- 0 7
S . B . 8 4 --- 2 8 --- 0 7
Page 4 of 12
01 Aug 2008
L.S
K. Publications Affected
ModSums Manual PSM 1- - -84- - -12..................................
L. References
The initial issue of this service bulletin was prepared to the engineering drawings
and related data that follows:
DRAWING SHEET REV
8DK4147 1 ---
ModSum 4- - -113580 Rev. - - -A
ModSum 4Q113580 Rev. - - -A
PCA 42424 (for internal reference only)

### Page 5

S E R V I C E B U L L E T I N 8 4 --- 2 8 --- 0 7
S . B . 8 4 --- 2 8 --- 0 7
Page 5 of 12
01 Aug 2008
L.S
2. MATERIAL INFORMA TION
A. Parts Required Per Aircraft
(1) No parts are required to accomplish the intent of this service bulletin.
(2) If it is required to dome seal the exposed threaded end of any terminal screw,
the following material(s) are required for the completion of this service
bulletin. The materials may be procured as single items from Bombardier
Aerospace Regional Aircraft or purchased directly from industry sources.
Addresses of manufacturers and suppliers not shown below are listed in the
Consumable Products Manual PSM 1- - -84- - -18
Part Number Qty. Per Aircraft Description Remarks
DHMS S3.01 1/4 Pint Typ e I or Typ e II
Class B Sealing
Compound, T em-
perature Resistant
DS108F 1/4 Pint Solvent, De- - -
greaser
Dynamold
As required Cotton, Lint free
Cloth
Sealant DHMS S3.01 available from:
PRC- - -Desoto Canada Inc.
5676 Timberlea Blvd.,
Mississauga, Ontario
L4W 4M6 Canada

### Page 6

S E R V I C E B U L L E T I N 8 4 --- 2 8 --- 0 7
S . B . 8 4 --- 2 8 --- 0 7
Page 6 of 12
01 Aug 2008
L.S
B. Parts Required to Modify Spares
None
C. Special T ools and Equipment Required
None
D. Existing Parts Accountability
None
3. ACCOMPLISHMENT INSTRUCTIONS
A . J o b S e t --- U p
(1) Make sure that lock pins are installed thru each main gear and main gear door
mechanism.
(2) Make sure the nose gear ground lock is engaged.
(3) Pressure defuel the applicable fuel tank (refer to TASK 12- - -10- - -28- - -650- - -802).
(4) Placard and select all aircraft electrical power to OFF . Obey all relevant
WARNINGS and CAUTIONS detailed in Maintenance Manual PSM 1- - -84- - -2
Chapter 24.
(5) Set up work platforms or ladders around and/or under the left (and/or right) wing
to permit access to the fuel tanks. Make sure that the work platforms or ladders
are electrically grounded.
(6) Make sure to obey the fuel system safety precautions (refer to AMM TASK
28- - -00- - -00- - -910- - -801.
(7) Obey the electrical/electronic safety precautions (refer to AMM TASK
24- - -00- - -00- - -910- - -801).
(8) Obey the electrostatic discharge safety precautions (refer to AMM TASK
24- - -00- - -00- - -910- - -802).

### Page 7

S E R V I C E B U L L E T I N 8 4 --- 2 8 --- 0 7
S . B . 8 4 --- 2 8 --- 0 7
Page 7 of 12
01 Aug 2008
L.S
(9) Remove the left and/or right wing panels that follow:
ACCESS DESIGNATION
524FT (and/or 624FT right wing) Outer Wing Fuel Access Panels
(a) For removal the outer wing fuel access panels refer to AMM TASK
57- - -21- - -01- - -000- - -801.
(10) Prepare fuel tank for access. Make sure no fuel or fuel vapors are present
before working on aircraft (refer to AMM TASK 28- - -10- - -00- - -840- - -801).
B. Procedure
Part A - - - Special Inspection
(1) Locate the high level sensor in the left and right side wing (between rib stations
Yw- - -389.019 and Yw- - -407.019) refer to Figure 1.
(a) Using a suitable light look at the inner side of the terminal block and
d e t e r m i n ei ft h et h r e a d e de n do fa l l3o ft h et e r m i n a lb l o c ks c r e w sa r eo r
are not completely covered with sealant (dome sealed) refer to Figure 2.
1 If the threaded end of all 3 terminal block screws are completely
covered with sealant (dome sealed ) refer to the close out section of
this service bulletin and return the aircraft to service.
2 If the threaded end of any terminal block screw is not completely
covered (dome sealed) refer to Part B - - - Rectificationthat follows.
Part B - - - Rectification - - - ModSum 4- - - 113580
(1) Dome seal the exposed threaded end of each terminal block screw on the inner
side of the high level sensor terminal block as follows (refer to Figure 2):
(a) Clean and degrease exposed threaded end of each terminal block screw
on the inner side of the high level sensor terminal block with solvent DS
108F (or equivalent).
(b) Dome seal the exposed threaded end of each terminal block screw with
sealant DHMS S3.01 Class B, T ype I or T ype II. Make sure the threaded
end of each terminal block screw is completely covered to reduce
possibility of wire contact (refer to AMM TASK 51- - -23- - -00- - -390- - -801).
NOTE: Proper application of sealant precludes the possibility of other wires in the
immediate area from making contact with the threaded end of each
terminal block screw.

### Page 8

S E R V I C E B U L L E T I N 8 4 --- 2 8 --- 0 7
S . B . 8 4 --- 2 8 --- 0 7
Page 8 of 12
01 Aug 2008
L.S
C. Close Out
(1) Install the left and/or right wing panels that follow:
ACCESS DESIGNATION
524AT (and/or 624AT right wing) Outer Wing Fuel Access Panels
(a) For installation the outer wing fuel access panels refer to PSM 1- - -84- - -2
TASK 57- - -21- - -01- - -400- - -801.
(2) Remove all tools equipment from the work area.
(3) On incorporation of this ModSum make an entry that conforms to local
regulatory requirements in the applic able logbook(s). Enter this ModSum
number only after complete incorporation of all work defined in this service
bulletin.

### Page 9

S E R V I C E B U L L E T I N 8 4 --- 2 8 --- 0 7
S . B . 8 4 --- 2 8 --- 0 7
Page 9 of 12
01 Aug 2008
L.S
High Level Sensor - - - Locator View
Figure 1 Sheet 1
S E EF I G U R E1S H E E T2
LEFT SIDE SHOWN
RIGHT SIDE SIMILAR

### Page 10

S E R V I C E B U L L E T I N 8 4 --- 2 8 --- 0 7
S . B . 8 4 --- 2 8 --- 0 7
Page 10 of 12
01 Aug 2008
L.S
High Level Sensor - - - Locator View
Figure 1 Sheet 2
Yw
- -317.019
Yw
- -335.019
Yw
- -353.019
Yw
- -371.019
Yw
- -389.019
Yw
- -407.019
FUEL QUANTITY
PROBE
2800- -TU9
VIEW LOOKING AFT
VIEW LOOKING DOWN
HIGH LEVEL
SENSOR
A
SEE DETAIL ‘A’
ON FIGURE 2

### Page 11

S E R V I C E B U L L E T I N 8 4 --- 2 8 --- 0 7
S . B . 8 4 --- 2 8 --- 0 7
Page 11 of 12
01 Aug 2008
L.S
High Level Sensor T erminal Block - - - Application of Sealant
Figure 2 Sheet 1
1
NOTE
1 Dome seal the exposed threaded
end of each terminal screw on
the inside of terminal block.
Refer to Fig 2 Sheet 2 for
additional view.
DETAIL A
VIEW LOOKING ON
HIGH LEVEL SENSOR
VIEW LOOKING ON FORWARD
FACE OF TERMINAL BLOCK
VIEW LOOKING ON INSIDE
OF TERMINAL BLOCK
TERMINAL BLOCK
1

### Page 12

S E R V I C E B U L L E T I N 8 4 --- 2 8 --- 0 7
S . B . 8 4 --- 2 8 --- 0 7
Page 12 of 12
01 Aug 2008
L.S
High Level Sensor T erminal Block - - - Application of Sealant
Figure 2 Sheet 2
END OF TERMINAL BLOCK SCREWS
TO BE COVERED WITH SEALANT
‘‘DOME SEALED’’
NOTE: 2 of 3 SCREWS SHOWN.
3’RD SCREW NOT IN VIEW
1

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain, except the copies of manufacturers’ service documents, which belong to their rights holders.