# Boeing Alert Service Bulletin 747-71A2329: U.S. DOT/FAA - SB-747-71A2329-00

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- Document: [Boeing Alert Service Bulletin 747-71A2329](https://openairdocs.org/service-documents/boeing/747-71a2329.md)
- Title as filed: U.S. DOT/FAA - SB-747-71A2329-00
- Pages: 40
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## Text

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### Page 1

Commercial
Airplanes
747
Service Bulletin
ALERT
Number: 747-71A2329
Original Issue: September 27, 2013
ATA System: 7121
SUBJECT: POWER PLANT - Engine Mounts - Forward Engine Mount Barrel Nut Inspection and
Replacement
Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15
CFR 300-774). 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 © 2013 Boeing.
Unpublished Work. All Rights Reserved.
Treatment of this document and its content is governed by contract with Boeing. Rights to use this document
are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The
Boeing Company.
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, KC-46, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8, Poseidon and
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connection with this document unless provided in writing by Boeing.
Original Issue: September 27, 2013
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Table of Contents
S u m m a r y ...................................................... 5
1. PLANNING INFORMATION ........................................ 9
A . E f f e c t i v i t y  ................................................ 9
1. Airplanes ............................................. 9
2 . S p a r e s  A f f e c t e d  ........................................ 1 0
B. Concurrent Requirements ...................................... 1 0
C. Reason ................................................ 1 0
D. Description .............................................. 1 1
E. Compliance .............................................. 1 2
F . A p p r o v a l  ............................................... 1 3
G. Manpower .............................................. 1 3
H. Weight and Balance Changes .................................... 1 4
I. Electrical Load Data ......................................... 1 4
J . R e f e r e n c e s  .............................................. 1 4
1. Existing Data: ......................................... 1 4
2. Data Supplied with this Service Bulletin: ........................... 1 5
3. Installation Drawings Used in the Preparation of this Service Bulletin: ........... 1 5
K. Publications Affected ........................................ 1 5
L. Interchangeability and Intermixability of Parts ........................... 1 5
M. Software Accomplishment Summary ................................ 1 5
2. MATERIAL INFORMATION ........................................ 1 7
A. Material - Price and Availability ................................... 1 7
B. Industry Support Information .................................... 1 7
C. Parts Necessary for Each Airplane ................................. 1 7
1 . K i t s / P a r t s  ............................................ 1 7
2. Parts and Materials Supplied by the Operator ........................ 1 7
3. Parts Modified and Reidentified ................................ 1 8
4. Parts Removed and Not Replaced .............................. 1 8
D. Parts Necessary to Change Spares ................................. 1 8
E. Special Tooling - Price and Availability ............................... 1 8
F. Special Tooling Necessary to do this Service Bulletin ....................... 1 8
3. ACCOMPLISHMENT INSTRUCTIONS .................................. 1 9
A. GENERAL INFORMATION ..................................... 1 9
B. WORK INSTRUCTIONS ....................................... 2 1
FIGURE 1: FORWARD ENGINE MOUNT BARREL NUT ULTRASONIC (UT) INSPECTION ..... 2 3
FIGURE 2: FORWARD ENGINE MOUNT BOLT AND BARREL NUT REPLACEMENT ........ 2 6
APPENDIX A: INSPECTION RESULTS REPORT .............................. 3 0
APPENDIX B: ULTRASONIC (UT) INSPECTION PROCEDURE ...................... 3 4
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Commercial
Airplanes
747
Service Bulletin
ALERT
SummaryNumber: 747-71A2329Original Issue: September 27, 2013
ATA System: 7121
SUBJECT: POWER PLANT - Engine Mounts - Forward Engine Mount Barrel Nut Inspection and
Replacement
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
Accomplishment of this service bulletin will make sure the barrel nuts on the forward engine mount do not have
a crack. A crack on both sides of the barrel nut will cause complete failure of the barrel nut. Complete failure of
two or more barrel nuts on the same engine reduces the load capacity of the forward engine mount and could
result in separation of an engine from the airplane. Separation of an inboard engine under power could result
in loss of control of the airplane.
An operator reported that while replacing the No.2 engine, the Non Destructive Test (NDT) inspection of the
barrel nuts on the forward engine mount revealed cracks on 2 out of 4 barrel nuts. The operator also discovered
1 cracked barrel nut on the No. 1 engine. This is the first reported occurrence on the 747-8. Also, The Boeing
Company did a NDT inspection of barrel nuts on a flight test airplane. There were 2 barrel nuts where a crack
had initiated on the No. 2 engine. These barrel nuts are located at the forward end of the strut box and are used
to fasten the forward engine mount to the strut. A barrel nut with a crack on one side will still be able to carry
ultimate load. A crack on both sides of the barrel nut will cause complete failure of the barrel nut. Boeing has
not received any reports of a barrel nut with a crack on both sides.
This service bulletin gives instructions to inspect the barrel nuts on the forward engine mount and replace barrel
nuts that have a crack. This will prevent the complete failure of barrel nuts that could result in the separation of
an engine from the airplane. This service bulletin also has operators report the results of barrel nut inspections
to Boeing, as well as sending any cracked parts to Boeing. The inspection reports will be used in the root cause
investigation of this issue.
Boeing will issue a service bulletin for terminating action of this issue after completion of the root cause
investigation.
Boeing Fleet Team Digest (FTD) 747 FTD 71-13001 is related to this service bulletin.
Boeing Service Related Problem (SRP) 747-8-SRP-71-0060 is related to this service bulletin.
Export Controlled ECCN: 9E991 - BOEING
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This table is provided to operators for planning purposes only. Refer to the applicable sections for more
information.
ReferenceAffectedPlanning Data
Paragraph 1.A.2., Spares AffectedNoSpares Affected
Paragraph 1.E., Compliance and Paragraph
1.F., Approval
YesAD Related
Paragraph 1.H., Weight and Balance ChangesNoWeight and Balance Change
Paragraph 1.I., Electrical Load DataNoElectrical Load Changed
Paragraph 1.K., Publications AffectedNoPublications Affected
Paragraph 1.K., Publications AffectedNoAirplane Flight Operations Affected (Flight Crew
Operations Manual and/or FAA Approved Air-
plane Flight Manual)
Paragraph 2.C.1., Kits/PartsNoKits/Parts Required
Paragraph 2.C.2., Parts and Materials Supplied
by the Operator
YesOperator Supplied Parts/Material
Paragraph 2.F., Special Tooling Necessary to
do this Service Bulletin
NoSpecial Tooling Required
ACTION
1. Do ultrasonic (UT) inspection of the barrel nuts on the forward engine mount for cracked barrel nuts
or removal and dye penetrant inspection of existing bolt and barrel nuts and installation of new or
serviceable bolt and barrel nuts on the forward engine mount.
Condition 1: No Crack Found During UT Inspection
a. Send inspection results report and any cracked bolts and barrel nuts to Boeing.
b. Repeat ultrasonic (UT) inspection of the barrel nuts on the forward engine mount for cracked barrel
nuts or removal and dye penetrant inspection of existing bolt and barrel nuts and installation of
new or serviceable bolt and barrel nuts on the forward engine mount.
Condition 2: Any Crack Found On Any Barrel Nut During UT Inspection
a. Do removal and dye penetrant inspection of existing bolt and barrel nuts and installation of new
or serviceable bolt and barrel nuts on the forward engine mount.
b. Send inspection results report and any cracked bolts and barrel nuts to Boeing.
c. Repeat ultrasonic (UT) inspection of the barrel nuts on the forward engine mount for cracked barrel
nuts or removal and dye penetrant inspection of existing bolt and barrel nuts and installation of
new or serviceable bolt and barrel nuts on the forward engine mount.
Condition 3: Barrel nuts replaced in accordance with removal and dye penetrant inspection of existing
bolt and barrel nuts and installation of new or serviceable bolt and barrel nuts on the forward engine
mount.
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a. Send inspection results report and any cracked bolts and barrel nuts to Boeing.
b. Repeat ultrasonic (UT) inspection of the barrel nuts on the forward engine mount for cracked barrel
nuts or removal and dye penetrant inspection of existing bolt and barrel nuts and installation of
new or serviceable bolt and barrel nuts on the forward engine mount.
EFFECTIVITY
All 747-8/-8F Airplane(s). Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplane(s).
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.
Refer to Paragraph 1.E., Compliance.
INDUSTRY SUPPORT INFORMATION
At the time of release of this service bulletin, warranty remedies have not been determined. A subsequent
revision or Information Notice will address the warranty remedies available, if any.
MANPOWER
Elapsed HoursTotal Task HoursEngines
6.006.00PART 1: ULTRASONIC (UT) INSPECTION OF BARREL
NUTS ON FORWARD ENGINE MOUNT
6.8016.40PART 2: REMOVAL AND DYE PENETRANT INSPECTION
OF EXISTING BOLT AND BARREL NUTS AND INSTALLA-
TION OF NEW OR SERVICEABLE BOLT AND BARREL
NUTS ON FORWARD ENGINE MOUNT
(a)(a)PART 3: SEND APPENDIX A INSPECTION RESULTS RE-
PORT AND ANY CRACKED BOLTS AND BARREL NUTS
(a) No manpower estimate was calculated for this task.
Refer to Paragraph 1.G., Manpower.
MATERIAL INFORMATION
Operator Supplied Parts/Materials.
Refer to Paragraph 2.A., Material - Price and Availability.
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BOEING SERVICE BULLETIN 747-71A2329
ALERT  ALERT
DO ULTRASONIC (UT) INSPECTION OF THE
BARREL NUTS ON THE FORWARD ENGINE
MOUNT FOR CRACKED BARREL NUTS OR
REMOVAL AND DYE PENETRANT
INSPECTION OF EXISTING BOLT AND
BARREL NUTS AND INSTALLATION OF NEW
OR SERVICEABLE BOLT AND BARREL NUTS
ON THE FORWARD ENGINE MOUNT
CONDITION 1: NO CRACK FOUND DURING UT
INSPECTION
-SEND INSPECTION RESULTS REPORT AND
ANY CRACKED BOLTS AND BARREL NUTS
TO BOEING
-REPEAT ULTRASONIC (UT) INSPECTION
OF THE BARREL NUTS ON THE FORWARD
ENGINE MOUNT FOR CRACKED BARREL
NUTS OR REMOVAL AND DYE PENETRANT
INSPECTION OF EXISTING BOLT AND
BARREL NUTS AND INSTALLATION OF
NEW OR SERVICEABI  E BOLT AND BARREL
NUTS ON THE FORWARD ENGINE MOUNT
CONDITION 2: ANY CRACK FOUND ON ANY
BARREL NUT DURING UT INSPECTION
-DO REMOVA  OYE PENETRANT
INSPECTION OF
BARREL NUTS  ISTALLATION OF NEW
OR SERVICEAB  E BOLT AND BARREL NUTS
ON THE FORWARD ENGINE MOUNT
-SEND INSPECTION RESULTS REPORT AND
ANY CRACKED BOLTS AND BARREL NUTS TO
BOEING
-REPEAT ULTRASONIC (UT) INSPECTION OF
THE BARREL NUTS ON THE FORWARD
ENGINE MOUNT FOR CRACKED BARREL
NUTS OR REMOVAL AND DYE PENETRANT
INSPECTION OF E  ING BOLT AND
BARREL NUTS A  ND INSTALLA  TION OF NEW
OR SERVICEAB  E BOLT AND BARREL NUTS
ON THE FORWARD ENGINE MOUNT
CONDITION 3: BARREL NUTS REPLACED IN
ACCORDANCE WITH REMOVAL AND DYE
PENETRANT INSPECTION OF EXISTING BOLT
AND BARREL NUTS AND INSTALLATION OF
NEW OR SERVICEABLE BOLT AND BARREL
NUTS ON THE FORWARD ENGINE MOUNT
-SEND INSPECTION RESULTS REPORT AND
ANY CRACKED BOLTS AND BARREL NUTS TO
BOEING
-REPEAT ULTRASONIC (UT) INSPECTION OF
THE BARREL NUTS ON THE FORWARD
ENGINE MOUNT FOR CRACKED BARREL
NUTS OR REMOVAL AND DYE PENETRANT
INSPECTION OF EXISTING BOLT AND BARREL
NUTS AND INSTALLATION OF NEW OR
SERVICEABLE BOLT AND BARREL NUTS ON
THE FORWARD ENGINE MOUNT
Original Issue: September 27, 2013
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Commercial
Airplanes
747
Service Bulletin
ALERT
Number: 747-71A2329
Original Issue: September 27, 2013
ATA System: 7121
SUBJECT: POWER PLANT - Engine Mounts - Forward Engine Mount Barrel Nut Inspection and
Replacement
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
Refer to Service Bulletin Index D6-30300 Part 3 for Airplane Variable Number, Line Number, and
Serial Number data.
This service bulletin is for the airplane(s) shown below.
NOTE: This service bulletin is for the airplanes shown in the effectivity list below. The effectivity
list includes all affected airplanes scheduled to be delivered before SEP 22, 2014. In
addition, at least one airplane scheduled to be delivered after SEP 22, 2014 is affected
by this service bulletin and is in Group(s) 1 as described in the Group Configuration table.
Affected airplanes will be added to the service bulletin's MyBoeingFleet.com (MBF) "get
effectivity" result when they are added to the MBF Fleet Profile Page.
DESCRIPTIONCONFIGURATIONGROUP
All 747-8/-8F airplanes.-1
Airplane Models:
747-8, 747-8F
GroupVariable Number
1RC001 - RC008
1RC022 - RC036
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GroupVariable Number
1RC066
1RC501 - RC509
1RC511
1RC521 - RC528
1RC541
1RC546 - RC549
1RC551 - RC563
1RC571 - RC572
1RC574 - RC582
1RC601 - RC605
1RC641 - RC642
1RC671 - RC672
2. Spares Affected
None.
B. Concurrent Requirements
None.
C. Reason
Accomplishment of this service bulletin will make sure the barrel nuts on the forward engine mount do
not have a crack. A crack on both sides of the barrel nut will cause complete failure of the barrel nut.
Complete failure of two or more barrel nuts on the same engine reduces the load capacity of the forward
engine mount and could result in separation of an engine from the airplane. Separation of an inboard
engine under power could result in loss of control of the airplane.
An operator reported that while replacing the No.2 engine, the Non Destructive Test (NDT) inspection
of the barrel nuts on the forward engine mount revealed cracks on 2 out of 4 barrel nuts. The operator
also discovered 1 cracked barrel nut on the No. 1 engine. This is the first reported occurrence on the
747-8. Also, The Boeing Company did a NDT inspection of barrel nuts on a flight test airplane. There
were 2 barrel nuts where a crack had initiated on the No. 2 engine. These barrel nuts are located at
the forward end of the strut box and are used to fasten the forward engine mount to the strut. A barrel
nut with a crack on one side will still be able to carry ultimate load. A crack on both sides of the barrel
nut will cause complete failure of the barrel nut. Boeing has not received any reports of a barrel nut
with a crack on both sides.
This service bulletin gives instructions to inspect the barrel nuts on the forward engine mount and
replace barrel nuts that have a crack. This will prevent the complete failure of barrel nuts that could
result in the separation of an engine from the airplane. This service bulletin also has operators report
the results of barrel nut inspections to Boeing, as well as sending any cracked parts to Boeing. The
inspection reports will be used in the root cause investigation of this issue.
Export Controlled ECCN: 9E991 - BOEING
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Boeing will issue a service bulletin for terminating action of this issue after completion of the root cause
investigation.
Boeing Fleet Team Digest (FTD) 747 FTD 71-13001 is related to this service bulletin.
Boeing Service Related Problem (SRP) 747-8-SRP-71-0060 is related to this service bulletin.
D. Description
1. Do ultrasonic (UT) inspection of the barrel nuts on the forward engine mount for cracked barrel
nuts or removal and dye penetrant inspection of existing bolt and barrel nuts and installation of
new or serviceable bolt and barrel nuts on the forward engine mount.
Condition 1: No Crack Found During UT Inspection
a. Send inspection results report and any cracked bolts and barrel nuts to Boeing.
b. Repeat ultrasonic (UT) inspection of the barrel nuts on the forward engine mount for cracked
barrel nuts or removal and dye penetrant inspection of existing bolt and barrel nuts and
installation of new or serviceable bolt and barrel nuts on the forward engine mount.
Condition 2: Any Crack Found On Any Barrel Nut During UT Inspection
a. Do removal and dye penetrant inspection of existing bolt and barrel nuts and installation of
new or serviceable bolt and barrel nuts on the forward engine mount.
b. Send inspection results report and any cracked bolts and barrel nuts to Boeing.
c. Repeat ultrasonic (UT) inspection of the barrel nuts on the forward engine mount for cracked
barrel nuts or removal and dye penetrant inspection of existing bolt and barrel nuts and
installation of new or serviceable bolt and barrel nuts on the forward engine mount.
Condition 3: Barrel nuts replaced in accordance with removal and dye penetrant inspection of
existing bolt and barrel nuts and installation of new or serviceable bolt and barrel nuts on the
forward engine mount.
a. Send inspection results report and any cracked bolts and barrel nuts to Boeing.
b. Repeat ultrasonic (UT) inspection of the barrel nuts on the forward engine mount for cracked
barrel nuts or removal and dye penetrant inspection of existing bolt and barrel nuts and
installation of new or serviceable bolt and barrel nuts on the forward engine mount.
The work in this service bulletin is done in the maintenance zone(s) given below.
Affected Maintenance Zones
ZoneModel
412, 422, 432, 442747-8, 747-8F
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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.
When more than one OPTION is given for a CONDITION, do only one of the OPTION numbers. When
more than one ACTION is given for a CONDITION number or an OPTION number, do all of the ACTION
numbers for that CONDITION number or OPTION number.
The Conditions, Actions and Compliance times shown apply to each engine independently.
Do the required actions in accordance with Paragraph 3. Accomplishment Instructions.
The following abbreviations are used in the compliance tables:
1. PART 1: UT INSPECTION refers to PART 1: ULTRASONIC (UT) INSPECTION OF BARREL
NUTS ON FORWARD ENGINE MOUNT.
2. PART 2: DYE PENETRANT INSPECTION refers to PART 2: REMOVAL AND DYE PENETRANT
INSPECTION OF EXISTING BOLT AND BARREL NUTS AND INSTALLATION OF NEW OR
SERVICEABLE BOLT AND BARREL NUTS ON FORWARD ENGINE MOUNT.
3. PART 3: SEND REPORT AND ANY CRACKED PARTS refers to PART 3: SEND APPENDIX A
INSPECTION RESULTS REPORT AND ANY CRACKED BOLTS AND BARREL NUTS.
Table 1: Inspection of the Barrel Nuts on the Forward Engine Mount
Repeat In-
terval (Not
to Ex-
ceed)
Compliance Time (Whichever occurs
later)
ActionCondition
200 flight
cycles (a)
Within 30
days after
the original
issue date
of this ser-
vice bul-
letin.
Within 200 flight cycles from
the date of issuance of the
original certificate of airwor-
thiness or the original ex-
port certificate of airworthi-
ness.
Do PART 1: UT INSPECTION
or
PART 2: DYE PENETRANT IN-
SPECTION. (b)
All Airplanes
--Within 10 days after accom-
plishment of PART 1: UT
INSPECTION.
ACTION 1:
Do PART 3: SEND REPORT AND
ANY CRACKED PARTS.
CONDITION 1: NO
CRACK FOUND
DURING UT IN-
SPECTION
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Table 1: Inspection of the Barrel Nuts on the Forward Engine Mount
Repeat In-
terval (Not
to Ex-
ceed)
Compliance Time (Whichever occurs
later)
ActionCondition
--Before further flight.ACTION 1:CONDITION 2:
ANY CRACK
FOUND ON ANY
BARREL NUT
DURING UT IN-
SPECTION
Do PART 2: DYE PENETRANT IN-
SPECTION. (b)
--Within 10 days after accom-
plishment of installation of
bolts and barrel nuts in ac-
cordance with PART 2:
DYE PENETRANT INSPEC-
TION.
ACTION 2:
Do PART 3: SEND REPORT AND
ANY CRACKED PARTS.
--Within 10 days after accom-
plishment of installation of
bolts and barrel nuts in ac-
cordance with PART 2:
DYE PENETRANT INSPEC-
TION.
ACTION 1:
Do PART 3: SEND REPORT AND
ANY CRACKED PARTS.
CONDITION 3:
BARREL NUTS
AND BOLTS RE-
PLACED IN AC-
CORDANCE WITH
PART 2: DYE
PENETRANT IN-
SPECTION
(a) No terminating action is given.
(b) Whenever PART 2: DYE PENETRANT INSPECTION is done, all bolts and barrel nuts on that engine
mount must be removed and replaced with new or serviceable parts.
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 and installation
for each engine. 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
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• Time to inspect the work
• Time to cure the materials
• Time to make the parts
• Time to find the tools.
PART 1: ULTRASONIC (UT) INSPECTION OF BARREL NUTS ON FORWARD ENGINE MOUNT
Elapsed HoursTask HoursNumber of PersonsTask
1.001.001Open Access
4.004.001FIGURE 1
1.001.001Close Access
6.006.00TOTAL FOR EACH ENGINE
PART 2: REMOVAL AND DYE PENETRANT INSPECTION OF EXISTING BOLT AND BARREL
NUTS AND INSTALLATION OF NEW OR SERVICEABLE BOLT AND BARREL NUTS ON
FORWARD ENGINE MOUNT
Elapsed HoursTask HoursNumber of PersonsTask
1.404.203Open Access
4.008.002FIGURE 2
1.404.203Close Access
6.8016.40TOTAL FOR EACH ENGINE
PART 3: SEND APPENDIX A INSPECTION RESULTS REPORT AND ANY CRACKED BOLTS
AND BARREL NUTS
Elapsed HoursTask HoursNumber of PersonsTask
---Send Report and
Parts
(a)(a)TOTAL FOR EACH ENGINE
(a) No manpower estimate was calculated for this task.
H. Weight and Balance Changes
None.
I. Electrical Load Data
Not changed.
J. References
1. Existing Data:
a. Boeing Service Related Problem (SRP) 747-8-SRP-71-0060
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b. Service Bulletin Index D6-30300
c. Standard Overhaul Practices Manual (SOPM) 20-50-01
d. Standard Wiring Practices Manual (SWPM) 20-10-11, 20-10-12, 20-10-19
e. 747 Fleet Team Digest (FTD) 71-13001
f. 747-8 Aircraft Maintenance Manual (AMM) 54-62-04, 71-00-00, 71-11-04, 71-21-03
2. Data Supplied with this Service Bulletin:
None.
3. Installation Drawings Used in the Preparation of this Service Bulletin:
TitleDrawing Number
ENGINE MOUNT TO STRUT MODULE - GENX-2B310U8010
The table above lists applicable drawings used to prepare this service bulletin. The drawings are
not necessary to make the specified changes, and are not supplied with this service bulletin. The
drawings may not be applicable to all airplane configurations or operators.
K. Publications Affected
1. Publications:
None.
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
Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts.
M. Software Accomplishment Summary
Not affected.
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### Page 17

2.    MATERIAL INFORMATION
A. Material - Price and Availability
The operator can supply the parts and materials shown in Paragraph 2.C., Parts Necessary for Each
Airplane. As an alternative, operators can purchase the parts from Boeing Spares. The Boeing price
data shown below is given for planning purposes. Supply data can be given if requested. 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)
QTYDateNamePart Number
$383.007614410/11/2013BARREL NUTSL4081C14SP1
85612/23/2013
$98.001461610/11/13BOLTBACB30US14-31M
18403/14/2014
B. Industry Support Information
At the time of release of this service bulletin, warranty remedies have not been determined. A subsequent
revision or Information Notice will address the warranty remedies available, if any.
C. Parts Necessary for Each Airplane
1. Kits/Parts
None.
2. Parts and Materials Supplied by the Operator
The following parts or materials are necessary to do the change in this service bulletin. Parts and
materials in the manuals given in Paragraph 1.J., References, can also be necessary. Examine
operator part and material supply to make sure all necessary parts and materials are available.
NotesNameQTYPart Number /
Specification
(b)BARREL NUT4 (a)SL4081C14SP1
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NotesNameQTYPart Number /
Specification
(c)BOLT4 (a)BACB30US14-31M
(d)MARKING LACQUER2
ounces
-
(a) Quantity of 4 required for each engine. Quantity may vary based on inspection results.
(b) Shur-Lock Company (97393), 2541 White Road Irvine, California 92614
(c) LISI Aerospace North America (727622), 2600 Skypark Drive Torrance, CA 90505
(d) F-925, Skydrol Resistant Torque Seal, Organic Products Company, PO Box 560625,
Dallas, TX 75356-0625 (MSDS41617)
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
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. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for
definition of the acronyms.
2. Obey all of the warnings and cautions given in the specified manual sections.
3. Unless shown differently, these dimensions and tolerances are used:
– Linear dimensions are in inches
– Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus
or minus 0.03 inch
– Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch
– Angular tolerance is plus or minus 2 degrees
– Hole dimensions for standard solid rivets and fasteners are in Structural Repair
Manual (SRM) Chapter 51
– Torque Values:
— Values for structural fasteners are given in 747 Structural Repair Manual,
Chapter 51.
— Values for airframe maintenance tasks are included in Chapter 20 of 747
Airplane Maintenance Manual (AMM).
— Values for electrical maintenance tasks are included in Chapter 20 of
Standard Wiring Practices Manual (SWPM).
— Values for engine maintenance tasks are included in Chapter 70 of 747
Airplane Maintenance Manual (AMM).
— Non-standard torque values for maintenance tasks are included in the
applicable installation step.
4. Use the approved fastener, process and material substitutions in accordance with
SRM Chapter 51.
5. Refer to the SWPM 20-10-11 and SWPM 20-10-12 for the wire installation procedures,
and SWPM 20-10-19 for the wire separation requirements, as accepted procedures.
6. The necessary conditions for selection of clamp type and size are included in SWPM
20-10-12. If any wire bundle support clamp specified in this service bulletin does not
make a correct fit on the wire bundle, refer to SWPM 20-10-12 as an accepted
procedure to select a clamp that fits correctly.
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7. If the length of any fastener specified in this service bulletin does not meet installation
standards given in SRM Chapter 51, then a fastener of the same specification, or
an approved substitute, with a length which meets the installation standards given
in SRM Chapter 51 may be used. In addition, washers may be installed for fastener
grip length in accordance with SRM Chapter 51. Refer to SOPM 20-50-01 for alternate
full threaded fasteners (screws) needed for installation in this service bulletin.
8. A Detailed Inspection (DET) is defined as: An intensive examination of a specific
item, installation, or assembly to detect damage, failure, or irregularity. Available
lighting is normally supplemented with a direct source of good lighting at an intensity
deemed appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may
be necessary. Surface cleaning and elaborate procedures may be required.
9. 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.
10. Refer to APPENDIX A for Inspection Results Report instructions.
11. Refer to APPENDIX B for Ultrasonic (UT) Inspection procedure.
12. The instructions in Paragraph 3.B., Work Instructions and the figures can include
operation of tools or test equipment. Boeing Engineering Tool Drawings, the Illustrated
Tool and Equipment Manual, and the Special Tool and Ground Handling Drawing
Index contain data on versions of the tools or test equipment that you can use. It is
permitted to use replaced tools. It is not permitted to use superseded tools.
13. If it is necessary to remove more parts for access, you can remove those parts. If
you can get access without removing identified parts, it is not necessary to remove
all of the identified parts. Jacking and shoring limitations must be observed.
14. Where the work instructions include installation of a kept part, a new or serviceable
part with the same part number can be installed as an alternative to the kept part.
15. If shading is used, shaded areas in Figures are to separate the non-critical and
non-authoritative information from the critical and authoritative information.
16. When more than one OPTION is given for a CONDITION, do only one of the OPTION
numbers. When more than one ACTION is given for a CONDITION number or an
OPTION number, do all of the ACTION numbers for that CONDITION number or
OPTION number.
17. The compliance times for the actions in Paragraph 3.B., WORK INSTRUCTIONS
are in Paragraph 1.E., Compliance.
18. The CONDITIONS, ACTIONS and OPTIONS shown apply to each engine
independently.
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19. Some steps in the Work Instructions are identified as Required for Compliance (RC).
If this service bulletin is mandated by an Airworthiness Directive (AD), then the steps
identified as RC must be done to comply with the AD. Alternative procedures for
steps not identified with RC can be used if the RC steps can still be done as specified,
and the airplane can be put back in a serviceable condition. An Alternative Method
of Compliance (AMOC) is not necessary for deviations to steps that are not identified
as RC.
B. WORK INSTRUCTIONS
1. Do PART 1: ULTRASONIC (UT) INSPECTION OF BARREL NUTS ON FORWARD ENGINE
MOUNT for cracked barrel nuts or PART 2: REMOVAL AND DYE PENETRANT INSPECTION
OF EXISTING BOLT AND BARREL NUTS AND INSTALLATION OF NEW OR SERVICEABLE
BOLT AND BARREL NUTS ON FORWARD ENGINE MOUNT.
CONDITION 1: NO CRACK FOUND DURING UT INSPECTION
a. ACTION 1: Do PART 3: SEND APPENDIX A INSPECTION RESULTS REPORT AND ANY
CRACKED BOLTS AND BARREL NUTS.
CONDITION 2: ANY CRACK FOUND ON ANY BARREL NUT DURING UT INSPECTION
a. ACTION 1: Do PART 2: REMOVAL AND DYE PENETRANT INSPECTION OF EXISTING
BOLT AND BARREL NUTS AND INSTALLATION OF NEW OR SERVICEABLE BOLT AND
BARREL NUTS ON FORWARD ENGINE MOUNT.
b. ACTION 2: Do PART 3: SEND APPENDIX A INSPECTION RESULTS REPORT AND ANY
CRACKED BOLTS AND BARREL NUTS.
CONDITION 3: BARREL NUTS REPLACED IN ACCORDANCE WITH PART 2: REMOVAL AND
DYE PENETRANT INSPECTION OF EXISTING BOLT AND BARREL NUTS AND INSTALLATION
OF NEW OR SERVICEABLE BOLT AND BARREL NUTS ON FORWARD ENGINE MOUNT
a. ACTION 1: Do PART 3: SEND APPENDIX A INSPECTION RESULTS REPORT AND ANY
CRACKED BOLTS AND BARREL NUTS.
2. Put the airplane back to a serviceable condition.
PART 1: ULTRASONIC (UT) INSPECTION OF BARREL NUTS ON FORWARD ENGINE MOUNT
1. Open fan cowl. Refer to 747-8 AMM 71-11-04 as an accepted procedure.
2. Prepare APPENDIX A Inspection Results Report.
3. RC - Do UT inspection of forward engine mount barrel nuts in accordance with FIGURE 1.
4. Close fan cowl. Refer to 747-8 AMM 71-11-04 as an accepted procedure.
PART 2: REMOVAL AND DYE PENETRANT INSPECTION OF EXISTING BOLT AND BARREL
NUTS AND INSTALLATION OF NEW OR SERVICEABLE BOLT AND BARREL NUTS ON FORWARD
ENGINE MOUNT
1. Remove fan cowl. Refer to 747-8 AMM 71-11-04 as an accepted procedure.
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2. Remove the No. 2 Forward Fairing. Refer to 747-8 AMM 54-62-04 as an accepted procedure.
3. Install the forward bootstrap tool assembly. Refer to 747-8 AMM 71-00-00 as an accepted procedure.
4. RC - Apply the load to the forward engine mount. Refer to 747-8 AMM 71-00-00 as an accepted
procedure.
NOTE: Apply the load to the forward engine mount to remove the tension load from the forward
engine mount bolts.
5. Prepare APPENDIX A Inspection Results Report.
6. RC - Replace barrel nuts and do dye penetrant inspection in accordance with FIGURE 2.
7. Remove the load to the forward engine mount. Refer to 747-8 AMM 71-00-00 as an accepted
procedure.
8. Remove the forward bootstrap tool assembly. Refer to 747-8 AMM 71-00-00 as an accepted
procedure.
9. Install the No. 2 Forward Fairing. Refer to 747-8 AMM 54-62-04 as an accepted procedure.
10. Install fan cowl. Refer to 747-8 AMM 71-11-04 as an accepted procedure.
PART 3: SEND APPENDIX A INSPECTION RESULTS REPORT AND ANY CRACKED BOLTS AND
BARREL NUTS
1. RC - Send Appendix A Inspection Results Report and any cracked bolts and barrel nuts to The
Boeing Company. Refer to APPENDIX A for instructions.
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BOEING SERVICE BULLETIN 747-71A2329
ALERT  ALERT
ORIENTATION SAME FOR ALL ENGINE LOCATIONS
000
ORIENTATION SAME FOR
ALL ENGINE LOCATIONS
FWD
FIGURE 1: FORWARD ENGINE MOUNT BARREL NUT ULTRASONIC (UT) INSPECTION
(SHEET 1 OF 3)
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### Page 24 (OCR)

BOEING SERVICE BULLETIN 747-71A2329
ALERT  ALERT
00
ORIENTATION SAME FOR ALL ENGINE LOCATIONS
LOCATION D
LOCATION B
LOCATION C
(2 3)  LOCATION A
LOCATIONS
ORIENTATION SAME FOR
ALL ENGINE LOCATIONS
FIGURE 1: FORWARD ENGINE MOUNT BARREL NUT ULTRASONIC (UT) INSPECTION
(SHEET 2 OF 3)
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### Page 25

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for each engine.
More DataQtyIdentificationNameTaskStep
Identify location of the barrel nut so that
the location can by recorded in AP-
PENDIX A.
4SL4081C14SP1BARREL NUTIdentify1
Do UT Inspection of barrel nuts for any
crack in accordance with APPENDIX B.
4SL4081C14SP1BARREL NUTInspect2
Record the location and UT inspection
results in APPENDIX A.
4SL4081C14SP1BARREL NUTRecord3
FIGURE 1: FORWARD ENGINE MOUNT BARREL NUT ULTRASONIC (UT) INSPECTION
(SHEET 3 OF 3)
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BOEING SERVICE BULLETIN 747-71A2329
ALERT  ALERT
ORIENTATION SAME FOR ALL ENGINE LOCATIONS
ORIENTATION SAME FOR
ALL ENGINE LOCATIONS
FWD  2285380
FIGURE 2: FORWARD ENGINE MOUNT BOLT AND BARREL NUT REPLACEMENT
(SHEET 1 OF 4)
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### Page 27 (OCR)

BOEING SERVICE BULLETIN 747-71A2329
ALERT  ALERT
2 3 5  WD
BOLT  4 LOCATIONS
ORIENTATION SAME FOR ALL ENGINE LOCATIONS
LOCATION D
LOCATION B
WASHER
BARREL
NUT
LOCATION C
2345  LOCATION A
4 LOCATIONS
ORIENTATION SAME FOR
RETAINER  ALL ENGINE LOCATIONS
1) 4 LOCATIONS
The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for each engine.
FIGURE 2: FORWARD ENGINE MOUNT BOLT AND BARREL NUT REPLACEMENT
(SHEET 2 OF 4)
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### Page 28

More DataQtyIdentificationNameTaskStep
Identify and mark the location and orien-
tation of the barrel nut so that the loca-
tion and orientation can by recorded in
APPENDIX A.
4SL4081C14SP1BARREL NUTIdentify1
If torque stripe is present, do a DET of
the torque stripe for evidence of fastener
rotation so that the results can be
recorded in APPENDIX A. Evidence of
fastener rotation is if the edges of the
torque stripe are not aligned across the
fastener and the structure.
4BACB30US14-31MBOLTInspect2
Refer to 747-8 AMM 71-00-00 as an ac-
cepted procedure.
4BACB30US14-31MBOLTRemove
Refer to 747-8 AMM 71-00-00 as an ac-
cepted procedure.
4BACW10BP14ACUWASHERRemove /
Keep
Refer to 747-8 AMM 71-00-00 as an ac-
cepted procedure.
4SL4081C14SP1BARREL NUTRemove
Refer to 747-8 AMM 71-00-00 as an ac-
cepted procedure.
4SLR4124C14RETAINERRemove /
Keep
(a) Do a dye penetrant inspection for any
crack in accordance with 747-8 AMM
71-21-03.
4BACB30US14-31MBOLTInspect3
(a) (b) Do a dye penetrant inspection for
any crack in accordance with 747-8
AMM 71-21-03.
4SL4081C14SP1BARREL NUTInspect
(a) Record the location, orientation, if
torque stripe is aligned and dye pene-
trant or UT inspection results in AP-
PENDIX A.
4SL4081C14SP1BARREL NUTRecord4
FIGURE 2: FORWARD ENGINE MOUNT BOLT AND BARREL NUT REPLACEMENT
(SHEET 3 OF 4)
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More DataQtyIdentificationNameTaskStep
(c) Refer to 747-8 AMM 71-00-00 as an
accepted procedure.
4BACB30US14-31MBOLTInstall
(New)
5
Refer to 747-8 AMM 71-00-00 as an ac-
cepted procedure.
4BACW10BP14ACUWASHERInstall
(Kept)
(c) Refer to 747-8 AMM 71-00-00 as an
accepted procedure.
4SL4081C14SP1BARREL NUTInstall
(New)
Refer to 747-8 AMM 71-00-00 as an ac-
cepted procedure.
4SLR4124C14RETAINERInstall
(Kept)
Apply a torque stripe to bolt head and
forward engine mount. Refer to Para-
graph 2.C.2., Parts and Materials Sup-
plied by the Operator for acceptable
material.
4-MARKING LAC-
QUER
Apply
(a) The dye penetrant inspection of the removed bolts and barrel nuts may be performed at a later time if new
bolts and barrel nuts are installed. Dye penetrant inspection must be performed in time to comply with
CONDITION 2, ACTION 2, or CONDITION 3, ACTION 1 of Paragraph 1.E., Compliance.
(b) No dye penetrant inspection is required for any barrel nut that was shown to be cracked during UT inspec-
tion. All other barrel nuts must be dye penetrant inspected.
(c) A serviceable part may be installed in place of a new part if the part has been dye penetrant inspected
since it was last removed from service and no crack was found.
FIGURE 2: FORWARD ENGINE MOUNT BOLT AND BARREL NUT REPLACEMENT
(SHEET 4 OF 4)
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BOEING SERVICE BULLETIN 747-71A2329
ALERT  ALERT
LOCATION C  LOCATION D
LOCATION A  LOCATION B
LEFT  RIGHT
LOOKING DOWN
(ORIENTATION SAME FOR ALL ENGINE LOCATIONS)
PART NUMBER OR  PART NUMBER OR
LOT NUMBER  LOT NUMBER
FORWARD
• FACE
LEFT  • RIGHT
SIDE  SIDE
AFT FACE
LEFT  RIGHT
LOOKING DOWN
(ORIENTATION SAME FOR ALL ENGINE LOCATIONS)
FIGURE A1: BARREL NUT LOCATION AND ORIENTATION  2285388
APPENDIX A: INSPECTION RESULTS REPORT
(SHEET 1 OF 4)
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### Page 31

Service Bulletin 747-71A2329
Airplane Registry, Variable or Line Number:
Date of Inspection:Flight Cycles:Flight Hours:
Barrel Nut
Being In-
stalled
(New /
Service-
able)
Location
of Crack
on Bolt or
Barrel Nut
(LEFT
SIDE /
RIGHT
SIDE /
BOTH
SIDES) (If
applica-
ble)
Barrel Nut
Lot Num-
ber
Location
of Lot
Number
on Barrel
Nut (For-
ward Face
/ Aft Face)
Torque
Stripe
Aligned
(Yes / No)
Crack
Found (Y /
N) on
(BOLT /
BARREL
NUT /
BOTH)
Inspection
Method
Used (UT /
DYE PENE-
TRANT)
Bolt and
Barrel Nut
Location
Engine
Number
A1
B
C
D
A2
B
C
D
A3
B
C
D
A4
B
C
D
REPORTING INSTRUCTIONS:
1. Record the airplane registry, variable or line number.
2. Refer to illustration above for bolt and barrel nut location and orientation.
APPENDIX A:  INSPECTION RESULTS REPORT
(SHEET 2 OF 4)
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3. Record which inspection method was used.
4. Report if any crack was found or if no crack was found for every barrel nut. Report if any crack was
found on any bolts that were dye penetrant inspected.
a. If no crack was found, mark "No".
b. If any crack was found, mark "Yes" and mark if the cracked part was the "Bolt", the "Barrel Nut"
or "Both".
NOTE: Step 5 through Step 9 are only required if PART 2: REMOVAL AND DYE PENETRANT
INSPECTION OF EXISTING BOLT AND BARREL NUTS AND INSTALLATION OF NEW OR
SERVICEABLE BOLT AND BARREL NUTS ON FORWARD ENGINE MOUNT was done.
5. Record inspection results of the torque stripe. If the torque stripe is aligned, mark "Yes". If the torque
stripe is not aligned, mark "No". If no torque stripe is present, mark "N/A".
6. Record which face of the barrel nut the lot number is on, the forward face or the aft face. Mark "Forward
Face" or "Aft Face"
7. Record the lot number of the barrel nut. The barrel nut has the lot number marked on either the forward
face or the aft face. The part number is marked on the opposite face from the lot number. If UT Inspection
was done, record if lot number was visible. (Lot Number Example: XX-XXX)
8. Report the location of any crack found for all cracked bolts and barrel nuts. Report which side of the
bolt or barrel nut was cracked. Report "Left Side, Right Side, or Both Sides".
9. Record if the barrel nut being installed in FIGURE 2 is a new barrel nut or a previously used barrel nut.
NOTE: This information may be used for the terminating action.
10. Send the inspection results report to Boeing through the Boeing Communication System (BCS).
11. Please provide any detailed explanation or comments about the cracked bolts or barrel nuts in the BCS
message to Boeing.
12. Send any cracked bolts or barrel nuts to:
Spares Distribution Center
Warranty and Overhaul Area, SSA 111
THE BOEING COMPANY
Attention: Chris Morrow/Constantine Kostakis
(425) 237-1425
Mail Code 04-AR
APPENDIX A:  INSPECTION RESULTS REPORT
(SHEET 3 OF 4)
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### Page 33

2201 S. 142nd St
PO BOX 3707 98124-2207 (This line is only required if shipped via U.S. Postal Service)
SEATAC WA 98168-3713
USA
APPENDIX A:  INSPECTION RESULTS REPORT
(SHEET 4 OF 4)
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### Page 34

BARREL NUT ULTRASONIC (UT) INSPECTION
1. PURPOSE
a. Use this ultrasonic procedure to detect cracks in the four barrel nuts of the forward engine mount.
This procedure will detect a crack that completely severs one side of the barrel nut.
2. EQUIPMENT
a. Instrument
(1) Use an ultrasonic flaw detector.
(2) A GE USM Go was used to develop this procedure, alternate instruments can be used.
b. Transducer
(1) Use a transducer that:
(a) Operates at 10 MHz.
(b) Is cylindrical in shape.
(c) Has a case diameter of 0.31 inch (7.9 mm), or less.
(d) Has a top mount micro-dot connector.
(e) Has a minimum length of 0.50 inch (12.7 mm) and a maximum length of 1.0 inch (25
mm), not including the connector.
(f) Does not have a delay line.
(2) The transducer that follows was used to help prepare this procedure but, alternate transducers
can be used:
(a) Gamma, 10.0 MHz/.187" P/N 389-084-180; GE Inspection Technologies.
c. Transducer Extension Handle
(1) Two transducer extension handles are recommended to help get access to the inspection
area. It is difficult to reach the inspection areas without the extensions.
(a) A 2 inch long (51 mm) extension handle is recommended to help examine the right and
left barrel nuts on the forward side and the right barrel nut on the aft side of the forward
engine mount. The transducer extension handle that follows was used to help prepare
this procedure but, alternate handles can be used:
1) SPC-604FX-2; EC-NDT
APPENDIX B:  ULTRASONIC (UT) INSPECTION PROCEDURE
(SHEET 1 OF 7)
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
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BOEING SERVICE BULLETIN 747-71A2329
ALERTALERT

### Page 35

(b) An 8 inch long (203 mm), flexible shaft, extension handle is recommended to help examine
the left barrel nut on the aft side of the forward engine mount. This extension handle is
used because the position of the de-icing duct on the left side of the engine restricts the
access to the barrel nut. The transducer extension handle that follows was used to help
prepare this procedure but, alternate handles can be used:
1) SPC-604FX-8; EC-NDT
d. Reference Standard
(1) Use an un-installed new or serviceable forward engine mount barrel nut for a reference
standard to calibrate the equipment.
(2) The barrel nuts are made from Inconel 718.
(3) The barrel nuts are 1.5 inches (38.1 mm) long.
3. PREPARATION FOR INSPECTION
a. Identify and get access to the inspection area on the airplane. Refer to the service bulletin.
b. Remove all dirt and grease from the inspection area that the transducer will touch.
c. Select the reference standard that will be used to calibrate the equipment. See para. 2.d. to select
the reference standard.
4. INSTRUMENT CALIBRATION
a. Connect the transducer to the instrument.
b. Set the instrument frequency to 10 MHz, or a broadband setting that includes 10 MHz.
c. Set the initial pulse to 0% full screen width. See Appendix B Figure B1.
d. If the material velocity can be adjusted on the instrument, set the velocity to 0.224
inches/microsecond (5.69 mm/microsecond).
e. Set the display to show a 2 inch (51 mm) screen range.
f. Identify the inspection area.
g. Select the optional transducer extension recommended for the applicable location of the barrel
nut to be examined. See Para. 2.c. (Transducer Extension Handle).
h. Put couplant on the flat surface of an un-installed new or serviceable barrel nut.
i. Put the transducer on the center of the barrel nut. (see Appendix B Figure B1, detail I and Appendix
B Figure B2)
APPENDIX B:  ULTRASONIC (UT) INSPECTION PROCEDURE
(SHEET 2 OF 7)
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
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BOEING SERVICE BULLETIN 747-71A2329
ALERTALERT

### Page 36

NOTE: Make sure that the transducer fully touches the barrel nut and is not at the location of the
retainer.
j. If the velocity and screen range have been adjusted as specified above, the signal from the threaded
bore in the barrel nut will occur at approximately 18% Full Screen Width (FSW) (0.39 inch (10
mm)). Adjust the gain so the threaded bore signal on the display to 90% Full Screen Height (FSH).
See Appendix B Figure B1, Detail II.
k. If necessary, adjust the range and delay to cause the threaded bore signal to occur at approximately
18% FSW (0.39 inch (10 mm) on a 2 inch (51 mm) screen range). See Appendix B Figure B1,
Detail II.
l. Move the transducer until it is aligned with the edge of the barrel nut. See Appendix B Figure B1,
detail III and Appendix B Figure B2.
NOTE: Do not permit the transducer to overhang the edge of the barrel nut since the transducer
will be restricted by the barrel nut bore of the engine mount hanger fitting during the
inspection on the airplane.
m. The signal from the back surface of the barrel nut will occur at approximately 75% FSW (1.5 inches
(38.1 mm) on a 2 inch (51 mm) screen range with the correct velocity). See Appendix B Figure
B1, Detail IV.
n. Adjust the gain to get the back surface signal height to 100% FSH.
o. Add 6dB of gain.
p. Crack indications will occur between 25% and 50% FSW.
5. INSPECTION PROCEDURE
a. Identify and get access to the inspection area.
b. A total of 4 barrel nuts will be examined. (Two on the forward side of the forward engine mount
and two on the aft side).
(1) Examine the two forward barrel nuts as follows:
(a) Put the transducer on the forward side of a barrel nut in the center of the nut to get a
signal to occur from the threaded hole. Keep the transducer against the retainer to help
guide the transducer. See Appendix B Figure B2.
NOTE: The 2 inch long (51 mm) transducer extension handle is recommended to help
examine the barrel nuts on the forward side of the engine mount.
(b) Move the transducer away from the center to the outer edge of the barrel nut until it stops
at the edge of the bore in the hanger fitting. Examine on both sides of the threaded hole.
See Appendix B Figure B2.
(c) Identify all barrel nuts as cracked if:
APPENDIX B:  ULTRASONIC (UT) INSPECTION PROCEDURE
(SHEET 3 OF 7)
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BOEING SERVICE BULLETIN 747-71A2329
ALERTALERT

### Page 37

1) A signal occurs between 25% and 50% FSW.
NOTE: The back surface signal of the barrel nut will not occur when the transducer
is positioned in the area of the threaded hole because the hole will block
the sound from reaching the back surface. Multiple reflections from the
threaded hole can occur. Appendix B Figure B1, Detail II shows the first
threaded hole reflection at approximately 18% FSW and the second multiple
at approximately 36% FSW. The amplitude of the threaded hole signals will
rise and fall together.
(2) Examine the two aft barrel nuts as follows:
NOTE: The two inch long (51 mm) transducer extension handle is recommended to examine
the right, aft barrel nut and the eight inch long (203 mm) handle is recommended to
examine the left, aft barrel nut.
(a) Put the transducer on the aft side of the of a barrel nut in the center of the nut to get a
signal to occur from the threaded hole. Keep the transducer against the retainer to help
guide the transducer. See Appendix B Figure B2.
(b) Move the transducer away from the center to the outer edge of the barrel nut until it stops
at the edge of the bore in the hanger fitting. Examine on both sides of the threaded hole.
See Appendix B Figure B2.
(c) Identify all barrel nuts as cracked if:
1) A signal occurs between 25% and 50% FSW.
2) The back surface signal is not displayed on the screen at approximately 75% FSW
when the transducer on the barrel nut is adjacent to either side of the barrel nut bore
and the retainer as shown in Appendix B Figure B2.
NOTE: The back surface signal of the barrel nut will not occur when the transducer
is positioned in the area of the threaded hole because the hole will block
the sound from reaching the back surface. Multiple reflections from the
threaded hole can occur. Appendix B Figure B1, Detail II shows the first
threaded hole reflection at approximately 18% FSW and the second multiple
at approximately 36% FSW. The amplitude of the threaded hole signals will
rise and fall together.
6. INSPECTION RESULTS
a. If a signal occurs between 25% and 50% FSW, the barrel nut must be considered cracked even
if the back surface signal is shown on the instrument display.
b. If no back surface signal occurs and no signal occurs between 25% and 50% FSW then:
(1) Make sure that there is sufficient couplant on the barrel nut.
(2) Make sure that the transducer is in good contact with the surface of the barrel nut.
APPENDIX B:  ULTRASONIC (UT) INSPECTION PROCEDURE
(SHEET 4 OF 7)
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: September 27, 2013
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BOEING SERVICE BULLETIN 747-71A2329
ALERTALERT

### Page 38

(3) Make sure that the transducer is not on the retainer.
(4) Off angle cracks can prevent the back surface signal from occurring. Reject the barrel nut if
a back surface signal does not occur on the instrument display.
APPENDIX B:  ULTRASONIC (UT) INSPECTION PROCEDURE
(SHEET 5 OF 7)
Export Controlled ECCN: 9E991 - BOEING
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Original Issue: September 27, 2013
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BOEING SERVICE BULLETIN 747-71A2329
ALERTALERT

### Page 39 (OCR)

BOEING SERVICE BULLETIN 747-71A2329
ALERT  ALERT
DISTANCE TO EDGE OF
THREADED HOLE (INCHES)
SN 0.386 in  100
THREADED  90
HOLE
SIGNAL  80
70
60 GATE
TRANSDUCER  50
EXTENSION  40
HANDLE
30
INITIAL-  20
PULSE
10
TRANSDUCER POSITION  20
ON BARREL NUT TO  20  30 40  50  60 70 80  90  100
GET THREADED HOLE SIGNAL
DETAIL I  THIS SIGNAL IS A MULTIPLE  THREADED HOLE SIGNAL
REFLECTION FROM THE  SIGNAL DISPLAY
THREADED BORE. IT WILL  DETAIL II
RISE AND FALL TOGETHER  GATE USE BY THE
WITH THE THREADED  HOLE SIGNAL THAT  MEASURE DISTANCE  INSTRUMENT TO
OCCURS AT 18% FSW  TO THE REFLECTOR,
BARREL NOT  NOT THE REJECT
LENGTH DIMENSION  AMPLITUDE
(INCHES)  BACK
INSPECTION  SURFACE  SIGNAL
AREA FOR A
CRACK TO
OCCUR  SA 1.493 DA  RA
100
90
80
70
60 GATE
50 /
TRANSDUCER  40
EXTENSION
HANDLE  30
INITIAL  20
PULSE
10
TRANSDUCER POSITION  10 20 30 40 50 60 70 80 90 100
ON BARREL NUT TO
GET BACK SURFACE SIGNAL  BACK SURFACE SIGNAL AND
DETAIL III  INSPECTION AREA
SIGNAL DISPLAY
DETAIL IV
FIGURE B1: TRANSDUCER POSITIONS AND SIGNAL DISPLAYS
APPENDIX B: ULTRASONIC (UT) INSPECTION PROCEDURE
(SHEET 6 OF 7)
Original Issue: September 27, 2013
Export Controlled ECCN: 9E991 - BOEING  141-11A2329
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.  39 of 40

### Page 40 (OCR)

BOEING SERVICE BULLETIN 747-71A2329
ALERT  ALERT
FORWARD ENGINE MOUNT
HANGER FITTING
TRANSDUCER POSITION FOR  LA
THREADED HOLE SIGNAL
- BARRE
— RETAINER
TRANSDUCER POSITIONS FOR
BACK SURFACE SIGNAL OR
POSSIBLE CRACK SIGNAL  LEF  RIGHT
A-A
FIGURE B2: TRANSDUCER POSITIONS  2285696
APPENDIX B: ULTRASONIC (UT) INSPECTION PROCEDURE
(SHEET 7 OF 7)
Original Issue: September 27, 2013
Export Controlled ECCN: 9E991 - BOEING  PROPRIETARY - Copyright @ Unpublished  747-71A2329
Work - See page 1 for details.  40 of 40

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