D

S.B. 84 ---28 ---07

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 PARTICULARLY SIGNIFICANT AND

URGES OPERATORS TO PROMPTLY EVALUATE THE CONTENTS

SUBJECT: Fuel --- Fuel Indication --- High Level Sensor --- Application of Sealant

to exposed end of Sensor Terminal Block Screws --- Special

Inspection and Rectification --- ModSum 4 ---113580

1. PLANNING INFORMATION

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
SERVICE BULLETIN 84 ---28 ---07

S.B. 84 ---28 ---07

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
SERVICE BULLETIN 84 ---28 ---07

S.B. 84 ---28 ---07

Page 3 of 12

01 Aug 2008

L.S

D. Compliance

Bombardier Inc. recommends incorporation 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

Organization No: DAO #93 ---Q ---02.

F. Manpower

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 MAN ---HOURS

Job Set ---Up 2.50*

Procedure 1.00

Test / RTS 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. Tooling --- Price and Availability

None

I. Weight and Balance

None

J. Electrical Load Data

Not affected
SERVICE BULLETIN 84 ---28 ---07

S.B. 84 ---28 ---07

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)
SERVICE BULLETIN 84 ---28 ---07

S.B. 84 ---28 ---07

Page 5 of 12

01 Aug 2008

L.S

2. MATERIAL INFORMATION

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 Type I or Type II

Class B Sealing

Compound, Temperature 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
SERVICE BULLETIN 84 ---28 ---07

S.B. 84 ---28 ---07

Page 6 of 12

01 Aug 2008

L.S

B. Parts Required to Modify Spares

None

C. Special Tools and Equipment Required

None

D. Existing Parts Accountability

None

3. ACCOMPLISHMENT INSTRUCTIONS

A. Job Set ---Up

(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).
SERVICE BULLETIN 84 ---28 ---07

S.B. 84 ---28 ---07

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

determine if the threaded end of all 3 of the terminal block screws are or

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 --- Rectification that 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, Type I or Type 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.
SERVICE BULLETIN 84 ---28 ---07

S.B. 84 ---28 ---07

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 applicable logbook(s). Enter this ModSum

number only after complete incorporation of all work defined in this service

bulletin.
SERVICE BULLETIN 84 ---28 ---07

S.B. 84 ---28 ---07

Page 9 of 12

01 Aug 2008

L.S

High Level Sensor --- Locator View

Figure 1 Sheet 1

SEE FIGURE 1 SHEET 2

LEFT SIDE SHOWN

RIGHT SIDE SIMILAR
SERVICE BULLETIN 84 ---28 ---07

S.B. 84 ---28 ---07

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
SERVICE BULLETIN 84 ---28 ---07

S.B. 84 ---28 ---07

Page 11 of 12

01 Aug 2008

L.S

High Level Sensor Terminal 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
SERVICE BULLETIN 84 ---28 ---07

S.B. 84 ---28 ---07

Page 12 of 12

01 Aug 2008

L.S

High Level Sensor Terminal 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