# Boeing Alert Service Bulletin MD90-74A002: No revision named

- Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2010-1043; AD 2011-03-09 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication.
- Document: [Boeing Alert Service Bulletin MD90-74A002](https://openairdocs.org/service-documents/boeing/md90-74a002.md)
- Title as filed: U.S. DOT/FAA - Service Bulletin
- Pages: 21
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## Text

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### Page 1

Commercial 
Airplanes
MD90
Service Bulletin
ALERT
Number: MD90-74A002
Original Issue: August 17, 2010
ATA System: 7400
SUBJECT: ENGINE IGNITION - Ignition - Change Fire Handle Shutoff System Wire Routing
Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15
CFR 730-774). An export license may be required before it is used for development, production or use by foreign
persons from specific countries. The controller of this data has the individual responsibility to abide by all export
laws.
9E991ECCN:
BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET
Copyright © 2010 The Boeing Company
Unpublished Work - All Rights Reserved
Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable
subject matter. Boeing also claims copyright in this document as a compilation and/or collective work.
This document includes proprietary information owned by The Boeing Company and/or one or more third parties.
Treatment of the document and the information it contains is governed by contract with Boeing. For more
information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124.
Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner,
BBJ, DC-8, DC-9, DC-10, KC-10, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the
Boeing livery are all trademarks owned by The Boeing Company; and no trademark license is granted in
connection with this document unless provided in writing by Boeing.
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Table of Contents
Summary ...................................................... 5
1. PLANNING INFORMATION ........................................ 9
A. Effectivity ................................................ 9
1. Airplanes ............................................. 9
2. Spares Affected ........................................ 1 1
B. Concurrent Requirements ...................................... 1 1
C. Reason ................................................ 1 1
D. Description .............................................. 1 1
E. Compliance .............................................. 1 1
F. Approval ............................................... 1 2
G. Manpower .............................................. 1 2
H. Weight and Balance Changes .................................... 1 2
I. Electrical Load Data ......................................... 1 2
J. References .............................................. 1 3
1. Existing Data: ......................................... 1 3
2. Data supplied with this Service Bulletin: ........................... 1 3
3. Installation Drawings Used in the Preparation of this Service Bulletin: ........... 1 3
K. Publications Affected ........................................ 1 3
L. Interchangeability and Intermixability of Parts ........................... 1 4
2. MATERIAL INFORMATION ........................................ 1 5
A. Material - Price and Availability ................................... 1 5
B. Industry Support Information .................................... 1 5
C. Parts Necessary For Each Airplane ................................. 1 5
1. Kits/Parts: ........................................... 1 5
2. Parts and Materials Supplied by the Operator: ........................ 1 6
3. Parts Modified and Reidentified: ............................... 1 7
4. Parts Removed and Not Replaced: .............................. 1 7
D. Parts Necessary to Change Spares ................................. 1 7
E. Special Tooling - Price and Availability ............................... 1 7
F. Special Tooling Necessary to do this Service Bulletin ....................... 1 7
3. ACCOMPLISHMENT INSTRUCTIONS .................................. 1 9
A. GENERAL INFORMATION ..................................... 1 9
B. WORK INSTRUCTIONS ....................................... 2 0
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Commercial 
Airplanes
MD90
Service Bulletin
ALERT
SummaryNumber: MD90-74A002Original Issue: August 17, 2010
ATA System: 7400
SUBJECT: ENGINE IGNITION - Ignition - Change Fire Handle Shutoff System Wire Routing
THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH
1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO
THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO
THE NEW OWNER.
CONCURRENT REQUIREMENTS
None.
BACKGROUND
The engine fire shutoff handles on the MD-90 airplanes are designed to shutoff fuel at both the wing spar's
mechanical fuel fire shutoff valve as well as the electrical solenoid controlled engine fuel shutoff valve in the
engine Hydromechanical Unit (HMU). The feature is unique to the MD-90 airplanes and would result in an
automatic shutoff of the fuel at the engine HMU when the affected fire handle is pulled. Due to the lack of
separation between engine wires, a latent failure in the fire handle fuel shutoff relay circuit has the potential of
causing a dual engine shutdown in the event any single engine fuel fire shutoff handle is actuated. Separating
the fire handle shutoff system wiring will minimize the possibility of multiple engine shutdown due to single event.
If not corrected, inadequate separation has the potential of causing a dual engine shutdown in the event any
single engine fuel fire shutoff handle is activated.
ACTION
This service bulletin provides instructions for operators to change the wire routing for the fire handle shutoff
system.
EFFECTIVITY
MD-90-30 Airplanes. Refer to Paragraph 1.A.1., Airplanes for the list of affected airplanes.
COMPLIANCE
The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service
bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin
mandatory.
Boeing recommends that the wire routing change for the fire handle shutoff system be done within 4,200
flight-hours after the original issue date on this service bulletin.
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INDUSTRY SUPPORT INFORMATION
Boeing warranty remedies are not available for the configuration changes given in this service bulletin.
MANPOWER
Elapsed HoursTotal Task HoursAirplanes
7.97.9MD-90-30
MATERIAL INFORMATION
Boeing supplied Parts/Materials.
Refer to Paragraph 2.A., Material - Price and Availability.
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BOEING SERVICE BULLETIN MD90-74A002
ALERT  ALERT
CHANGE FIRE HANDLE SHUTOFF SYSTEM WIRE ROUTING
1920012
Original Issue: August 17, 2010
MD90-74A002
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Commercial 
Airplanes
MD90
Service Bulletin
ALERT
Number: MD90-74A002
Original Issue: August 17, 2010
ATA System: 7400
SUBJECT: ENGINE IGNITION - Ignition - Change Fire Handle Shutoff System Wire Routing
THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH
1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO
THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO
THE NEW OWNER.
1.    PLANNING INFORMATION
A. Effectivity
1. Airplanes
This service bulletin is for the airplanes shown below:
DESCRIPTIONCONFIGURATIONGROUP
Change Fire Handle Shutoff System Wire Routing-1
Airplane Models:
MD-90-30
GroupFuselage Num-
ber
12094 - 2100
12115
12117
12120
12122 - 2123
12125 - 2126
12129
12131
12133
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GroupFuselage Num-
ber
12136
12138
12140 - 2144
12146 - 2147
12149 - 2150
12153 - 2154
12156 - 2159
12161 - 2166
12169 - 2171
12173
12175
12177
12179
12181 - 2182
12184
12186
12190 - 2191
12193 - 2195
12197 - 2198
12200
12202 - 2203
12205
12207
12209 - 2213
12215 - 2217
12219 - 2233
12235 - 2237
12240
12243
12245
12248
12250 - 2251
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GroupFuselage Num-
ber
12253
12255 - 2263
12288 - 2290
14001 - 4002
2. Spares Affected
None.
B. Concurrent Requirements
None.
C. Reason
The engine fire shutoff handles on the MD-90 airplanes are designed to shutoff fuel at both the wing
spar's mechanical fuel fire shutoff valve as well as the electrical solenoid controlled engine fuel shutoff
valve in the engine Hydromechanical Unit (HMU). The feature is unique to the MD-90 airplanes and
would result in an automatic shutoff of the fuel at the engine HMU when the affected fire handle is
pulled. Due to the lack of separation between engine wires, a latent failure in the fire handle fuel shutoff
relay circuit has the potential of causing a dual engine shutdown in the event any single engine fuel
fire shutoff handle is actuated. Separating the fire handle shutoff system wiring will minimize the
possibility of multiple engine shutdown due to single event. If not corrected, inadequate separation has
the potential of causing a dual engine shutdown in the event any single engine fuel fire shutoff handle
is activated.
D. Description
This service bulletin provides instructions for operators to change the wire routing for the fire handle
shutoff system.
The work in this service bulletin is done in the maintenance zone(s) given below.
Affected Maintenance Zones
ZoneModel
114, 211MD-90-30
E. Compliance
The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to
this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this
service bulletin mandatory.
Boeing recommends that the wire routing change for the fire handle shutoff system be done within
4,200 flight-hours after the original issue date on this service bulletin.
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F. Approval
This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified
in this service bulletin comply with the applicable regulations and are FAA approved, as well as European
Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved
airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on
the airplane in its original Boeing delivery configuration or as modified by other approved Boeing
changes.
If an airplane has a non-Boeing modification or repair that affects a component or system also affected
by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval
before incorporating this service bulletin.
G. Manpower
The table below shows an estimate of the task hours necessary to do this inspection/modification for
each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate
with operator task hour data if necessary. The estimate does not include lost time. These are some
examples of lost time:
 Time to adjust to the workplace
 Time to schedule the work
 Time to inspect the work
 Time to cure the materials
 Time to make the parts
 Time to find the tools.
Elapsed HoursTask HoursNumber of PersonsTask
0.20.21Open Circuit Breaker
0.50.51Open Access
6.56.51Change and Coil/Stow
Wires
0.20.21Close Circuit Breaker
0.50.51Close Access
7.97.9TOTAL FOR EACH AIRPLANE
H. Weight and Balance Changes
Moment Change
(MEW) IN.-LBS
Mfr's Empty
Weight (MEW)
LBS
Approximate Sta-
tion (Inches)Airplane
+ 84.0+ 0.6+ 140.0MD-90-30
I. Electrical Load Data
Not changed.
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J. References
1. Existing Data:
a. Standard Wiring Practices Manual (SWPM) 20-00-03, 20-00-09, 20-00-13, 20-00-16, 20-10-01,
20-10-04, 20-20-01, 20-20-02, 20-31-00.
b. MD90 Aircraft Maintenance Manual (AMM) 06-31-00, 06-32-00, 24-00-00.
2. Data supplied with this Service Bulletin:
No data is supplied with this service bulletin. To obtain the data necessary to support this service
bulletin submit a data request to:
Data and Services Management
MS D800-0019
3855 Lakewood Boulevard
Long Beach, California 90846
Phone: (562) 593-6996
Fax: (562) 593-2001
E-mail: dse.boecom@boeing.com
a. Drawings:
ADCNDCN/REVSheetTitleDrawing No
-CDWGFIRE HANDLE SHUTOFF SYS WIRE
SEPARATION
SR90740002
3. Installation Drawings Used in the Preparation of this Service Bulletin:
ChangeTitleDocument Number
BRWIRE INSTALLATION - UPPER
NOSE
5964560
DDWIRE INSTALLATION - LOWER
NOSE
5964562
BJWIRE INSTALLATION - ELECTRI-
CAL POWER CENTER, OVHD SW
PNLS & HOUSING
5964566
These drawings were used to prepare this service bulletin. These drawings are not necessary to
make the specified changes, and are not supplied with this service bulletin. These drawings may
not be applicable to all airplane configurations or operators.
K. Publications Affected
1. Publications:
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Chapter-SectionPublication
26-11-013, 74-11-011, 74-11-012Wiring Diagram Manual
2. Damage Tolerance Based Structural Inspections:
Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue
Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the
Maintenance Program. This service bulletin does not affect FCS, therefore DTIs are not necessary.
L. Interchangeability and Intermixability of Parts
Refer to Paragraph 2.C., Parts Necessary for Each Airplane, for interchangeability and intermixability
information.
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2.    MATERIAL INFORMATION
A. Material - Price and Availability
Boeing can supply the parts shown in Paragraph 2.C., Parts Necessary for Each Airplane. Operators
are encouraged to share schedule requirements with Boeing for incorporation of the service bulletin.
The parts are subject to the terms and conditions of the Boeing standard purchase order
acknowledgment. Prices are in United States Dollars. Terms: Net 30 days.
Reference this service bulletin and submit your purchase order by one of these methods:
1. Order on-line via ATA Spec 2000 or The Boeing PART Page
2. Fax to (206) 662-7145
REFER TO THE BOEING PART PAGE ON MYBOEINGFLEET.COM OR CONTACT FIRST RESPONDER
AT FR@BOEING.COM FOR THE LATEST REORDER LEAD TIME (ROLT) AND PRICE INFORMATION
Unit Price as of
the original issue
date of this Ser-
vice Bulletin (US
Dollars)
ROLT as of the
original issue
date of this Ser-
vice Bulletin (Cal-
endar Days)
NameKit Number
$489.0090Service KitSA90740002-3
B. Industry Support Information
Boeing warranty remedies are not available for the configuration changes given in this service bulletin.
C. Parts Necessary For Each Airplane
1. Kits/Parts:
Kit SA90740002
NotesExisting Part NumberNameQTYNew Part Number
-101-3
--SA90740002-3
WIRE PACKAGE-1SA90740002-101
DMS 2109SLEEVE-.125 I.D. X
310 IN.
SR90740002-3
(a)
END CAP, T/C
914
-10CYW20
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Kit SA90740002
NotesExisting Part NumberNameQTYNew Part Number
-101-3
Remove and in-
stall socket or pin.
Refer to SWPM
20-00-16.
SOCKET, T/C
1123
-1DC39-16S
SOCKET, T/C
1124
-1DC39-20S
(b)WIRE CODE 801310 IN.-D2426-1C-20NM
SLEEVE2-SA90740002-5
(1/8 DIA X 2.0
INCHES)
(DMS 2399, Type 3
or Equivalent)
TAG2-DPM 6101
(a) SR90740002-5 (DMS 2379) sleeving is an approved alternate for SR90740002-3 (DMS 2109) sleeving.
(b) Refer to SWPM 20-00-13 Table 206 for approved alternate wires.
2. Parts and Materials Supplied by the Operator:
NotesNameQTYPart Number/ Specifi-
cation
(a)STRAP, TIEDOWNAs Required9D0254-1-1-9
or
(b)(PLT2S-9 or SST2S-9)
or
Equivalent
(c)TAPE, LACING & TYINGAs Required18 DZ BLK
(DPM 731-6)
or
Equivalent
TAPE, TYPING, GLASS FIBERAs Required18XTZ or 23XTZ
(DMS 2089)
or
Equivalent
CAGEThe Boeing Company(a) Can be purchased from:
812057755 East Marginal Way South
Seattle, Washington 98108
06383Panduit Corporation(b) Can be purchased from:
17301 Ridgeland Avenue
Tinley Park, Illinois 60477
7F993Gudebrod, Incorporated(c) Can be purchased from:
262 King Street
Pottstown, Pennsylvania 19464
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3. Parts Modified and Reidentified:
None.
4. Parts Removed and Not Replaced:
None.
D. Parts Necessary to Change Spares
None.
E. Special Tooling - Price and Availability
None.
F. Special Tooling Necessary to do this Service Bulletin
No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance
and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine
operator tool supply to make sure all necessary tools are available.
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3.    ACCOMPLISHMENT INSTRUCTIONS
A. GENERAL INFORMATION
WARNING: IF ELECTRICAL POWER IS APPLIED TO THE AIRPLANE, MAKE SURE YOU OBEY
ALL PRECAUTIONS WHILE YOU DO WORK. IF YOU DO NOT OBEY THE
PRECAUTIONS, DEATH OR INJURY TO PERSONS, AND DAMAGE TO THE AIRPLANE
CAN OCCUR.
CAUTION: ELECTRICALLY GROUND THE AIRPLANE. THIS WILL HELP TO PREVENT DAMAGE
TO THE AIRPLANE OR EQUIPMENT.
CAUTION: KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL
PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL,
METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE
DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR
OTHER ELECTRICAL DAMAGE.
NOTE: 1. The instructions identified in Paragraph 3.B., Work Instructions, and the Figure(s)
give the recommended sequence of steps. The sequence of steps to do this service
bulletin can be changed.
2. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for
definition of the acronyms.
3. Equivalent parts are listed in the AEPL, Drawing 7595071.
4. Refer to these SWPM chapters for applicable operations, as accepted procedures:
– SWPM 20-00-03 - Identification of Electrical wires.
– SWPM 20-00-09 - Electrical Identification and Shop Practice.
– SWPM 20-00-13 - Alternate wire type list.
– SWPM 20-00-16 - Electrical Wire End Termination Codes.
– SWPM 20-10-01 - Wire Installation Procedures.
– SWPM 20-10-04 - Coil and Stow Excess wire Length.
– SWPM 20-20-01 - Copper Electrical Terminals - Commercial.
– SWPM 20-20-02 - Terminal Junction Blocks - Commercial.
– SWPM 20-31-00 - Electrical Connectors - General Requirement - Commercial.
5. Review and understand all general notes of Service Rework Drawing SR90740002,
sheets 3.0 and 3.1.
6. Obey all of the warnings and cautions given in the specified manual sections.
7. These work instructions refer to procedures included in other Boeing documents.
When the words "refer to" are used and the operator has an accepted alternative
procedure, the accepted alternative procedure can be used. When the words "in
accordance with" are included in the instruction, the procedure in the Boeing document
must be used.
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B. WORK INSTRUCTIONS
1. Remove electrical power from airplane. Refer to MD90 AMM 24-00-00 as an accepted procedure.
2. Gain access to area of modification by opening the access doors as follows:
MORE DATALOCATIONACCESS DOOR
MD90 AMM 06-31-00Electrical/Electronic (E/E) Com-
partment
110BL
MD90 AMM 06-32-00Upper Nose Pedestal Floor,
STA 120.000
Wire Trough Cover
MD90 AMM 06-32-00Forward Cabin EPCElectrical Power Center (EPC)
Shroud
3. Open circuit breakers and install safety tags as follows:
NameNumberRow/ColLocation
Left Engine Start SwitchB1-1097U/34Lower EPC
Right Engine Start SwitchB1-1096X/39Lower EPC
Left Fuel Shutoff SolenoidB1-1079Z/32Lower EPC
Fire Warning LightsB1-192W/42Lower EPC
Right Fuel Shutoff SolenoidB1-1080B/10Overhead Panel
4. Disconnect, coil and stow existing wire in accordance with Service Rework Drawing SR90740002,
sheet 7.0.
5. Install new wire in accordance with Service Rework Drawing SR90740002, sheet 7.0.
6. Disconnect, coil and stow wires in accordance with Service Rework Drawing SR90740002, sheets
4.0, 4.1, 6.7, 6.8, and General Notes 16 and 20.
7. Do a continuity check on new wire.
8. Remove safety tags and close circuit breakers as follows:
NameNumberRow/ColLocation
Left Engine Start SwitchB1-1097U/34Lower EPC
Right Engine Start SwitchB1-1096X/39Lower EPC
Left Fuel Shutoff SolenoidB1-1079Z/32Lower EPC
Fire Warning LightsB1-192W/42Lower EPC
Right Fuel Shutoff SolenoidB1-1080B/10Overhead Panel
9. Close the access doors as follows:
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MORE DATALOCATIONACCESS DOOR
MD90 AMM 06-31-00Electrical/Electronic (E/E) Com-
partment
110BL
MD90 AMM 06-32-00Upper Nose Pedestal Floor,
STA 120.000
Wire Trough Cover
MD90 AMM 06-32-00Forward Cabin EPCElectrical Power Center (EPC)
Shroud
10. Restore electrical power to airplane. Refer to MD90 AMM 24-00-00 as an accepted procedure.
11. Put the airplane back to a serviceable condition.
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