# Boeing Alert Service Bulletin 737-27A1302: No revision named

- Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2012-0801; AD 2012-20-06 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication.
- Document: [Boeing Alert Service Bulletin 737-27A1302](https://openairdocs.org/service-documents/boeing/737-27a1302.md)
- Title as filed: U.S. DOT/FAA - SB-737-27A1302-00--[1]
- Pages: 44
- PDF: https://openairdocs.org/files/sha256/cf/67/cf67845488cb8b00439b2386550ab506cb5b59fefab52adf894543f27f2a082b
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## Text

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### Page 1

Commercial 
Airplanes
737
Service Bulletin
ALERT
Number: 737-27A1302
Original Issue: April 24, 2012
ATA System: 2731
SUBJECT: FLIGHT CONTROLS - Elevator Tab Control Mechanism Detailed Inspection
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 © 2012 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Unpublished Work - All Rights Reserved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
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Table of Contents
Summary ...................................................... 5
1. PLANNING INFORMATION ........................................ 9
A. Effectivity ................................................ 9
1. Airplanes ............................................. 9
2. Spares Affected ........................................ 1 4
B. Concurrent Requirements ...................................... 1 4
C. Reason ................................................ 1 4
D. Description .............................................. 1 4
E. Compliance .............................................. 1 5
F. Approval ............................................... 1 6
G. Manpower .............................................. 1 6
H. Weight and Balance Changes .................................... 1 8
I. Electrical Load Data ......................................... 1 8
J. References .............................................. 1 8
1. Existing Data .......................................... 1 8
2. Data supplied with this Service Bulletin ............................ 1 8
3. Installation Drawings Used in the Preparation of this Service Bulletin ............ 1 8
K. Publications Affected ........................................ 1 8
L. Interchangeability and Intermixability of Parts ........................... 1 9
2. MATERIAL INFORMATION ........................................ 2 1
A. Material - Price and Availability ................................... 2 1
B. Industry Support Information .................................... 2 1
C. Parts Necessary For Each Airplane ................................. 2 1
1. Kits/Parts ............................................ 2 1
2. Parts and Materials Supplied by the Operator ........................ 2 1
3. Parts Modified and Reidentified ................................ 2 1
4. Parts Removed and Not Replaced .............................. 2 1
D. Parts Necessary to Change Spares ................................. 2 1
E. Special Tooling - Price and Availability ............................... 2 1
F. Special Tooling Necessary to do this Service Bulletin ....................... 2 1
3. ACCOMPLISHMENT INSTRUCTIONS .................................. 2 3
A. GENERAL INFORMATION ..................................... 2 3
B. WORK INSTRUCTIONS ....................................... 2 4
FIGURE 1: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - LEFT SIDE ....... 2 9
FIGURE 2: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - LEFT SIDE ...... 3 3
FIGURE 3: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - RIGHT SIDE ...... 3 7
FIGURE 4: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - RIGHT SIDE ..... 4 1
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Commercial 
Airplanes
737
Service Bulletin
ALERT
SummaryNumber: 737-27A1302Original Issue: April 24, 2012
ATA System: 2731
SUBJECT: FLIGHT CONTROLS - Elevator Tab Control Mechanism Detailed Inspection
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
Boeing previously received a report from an 737NG operator where the failure of the aft attach lugs on the left
elevator tab control mechanism resulted in unwanted elevator freeplay vibration during flight. Investigation
revealed that the fractured aft attach lugs on the elevator tab control mechanism allowed freeplay of the
mechanism, which led to vibration of the elevator during flight. Further investigation revealed that the bearings
installed in the elevator tab control mechanism aft attach lugs were likely insufficiently swaged and became
loose. 737NG service bulletin 737-27A1297 was issued to do a detailed inspection for looseness of these
bearings. This service bulletin does inspection of these bearings for looseness similar to the inspections in
737-27A1297. Although the previously mentioned incident occurred on a 737NG, the design of the bearing lug
retention is essentially the same as newer 737-200's which all have the 65-45190-7 & -8 Tab Control Mechanism
installation. A loose bearing in the aft lug of the elevator tab control mechanism could lead to unwanted elevator
tab freeplay and then tab vibration which could lead to structural failure of the elevator or the horizontal stabilizer
which can result in unsafe flight conditions.
This bulletin will ensure the integrity of bearing swages, whether performed in production or during any subsequent
maintenance work done by an airline. This inspection was determined to be needed for the 737-200 because
the design of the 737-200 bearing retention is essentially the same as for the 737NG. The 737NG event showed
that the design used on both the 737-200 and the 737NG using the specification for installing the swage
(BAC5435) may not be adequate.
The related Elevator Tab service bulletin is 737-27A1297.
ACTION
Group 1:
Contact Boeing to get instructions for inspection, change and/or repair for this service bulletin, and do the work
instructed by Boeing.
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### Page 6

Group 2:
Remove access panels to gain access to the elevator tab control mechanism (mechanism) and do a detailed
inspection of the aft attach lugs (lugs). Look for rotation of the spacer. Also, use a feeler gage to check for any
gaps at certain locations. If there is a gap or a loose spacer, then replace the mechanism per the AMM and this
SB. If there is no gap or a loose spacer, then return the airplane to a serviceable condition.
Do repeat inspections of the mechanism at the times shown in paragraph 1.E., compliance.
EFFECTIVITY
737-200, 200C 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.
Refer to Paragraph 1.E., Compliance.
INDUSTRY SUPPORT INFORMATION
Boeing warranty remedies are not available for the inspection, and/or repair procedures given in this service
bulletin.
MANPOWER
Refer to Paragraph 1.G., Manpower.
MATERIAL INFORMATION
None.
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BOEING SERVICE BULLETIN 737-27A1302
ALERT  ALERT
DO A DETAILED
INSPECTION OF THE
ELEVATOR TAB
CONTROL MECHANISM
AFT LUGS
SURROUNDING STRUCTURE NOT SHOWN FOR CLARITY  2129600
Original Issue: April 24, 2012
737-27A1302
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Commercial 
Airplanes
737
Service Bulletin
ALERT
Number: 737-27A1302
Original Issue: April 24, 2012
ATA System: 2731
SUBJECT: FLIGHT CONTROLS - Elevator Tab Control Mechanism Detailed Inspection
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
DESCRIPTIONCONFIGURATIONGROUP
737-200, 200C Airplanes Line Number 288 to 291; Contact Boeing-1
737-200, 200C Airplanes Line Number 292 to 1585-2
Airplane Models:
737-200, 737-200C
GroupVariable Number
2PG584 - PG586
2PH001
2PH011 - PH013
2PH021 - PH024
1PH742
2PH743
2PJ003 - PJ009
2PJ105 - PJ119
2PJ201 - PJ219
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GroupVariable Number
2PK026 - PK029
2PK041 - PK053
2PK061 - PK070
2PK081 - PK082
2PK091 - PK099
2PK101 - PK103
2PK111 - PK120
2PK141 - PK146
2PK201 - PK204
2PK211 - PK223
2PK231 - PK241
2PK251 - PK258
2PK271 - PK274
2PK281 - PK289
2PK291
2PK301 - PK318
2PK341
2PK351 - PK361
2PK391
2PK431 - PK433
2PK451 - PK452
2PK461 - PK469
2PK495
2PK501 - PK504
2PK511 - PK515
2PK519
2PK521 - PK528
2PK541 - PK565
2PK581
2PK591 - PK599
2PK601 - PK617
2PK621 - PK637
2PK641 - PK642
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GroupVariable Number
2PK661 - PK666
2PK671 - PK681
2PK691 - PK697
2PK711 - PK716
2PK731 - PK765
2PK771 - PK779
2PK801 - PK804
2PK819 - PK827
2PK830
2PK861 - PK863
2PK871 - PK874
2PK881 - PK884
2PK901 - PK938
2PK971 - PK974
2PL001 - PL028
2PL061
2PL081
2PL101 - PL113
2PL151
2PL171 - PL172
2PL201 - PL203
2PL221
2PL401 - PL417
2PL421
2PL441
2PL451 - PL456
2PL471
2PL491
2PL501 - PL506
2PL551 - PL562
2PL581
2PL601 - PL603
2PL611
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GroupVariable Number
2PL621 - PL626
2PL631 - PL632
1PL712
1PL716
2PL717 - PL747
2PL756
2PL758
2PL761 - PL770
2PL781 - PL788
2PL793
2PM001 - PM006
2PM016 - PM017
2PM021 - PM023
2PM051 - PM066
2PM101 - PM119
2PM141 - PM142
2PM171
2PM181
2PM251 - PM255
2PM281 - PM283
2PN001 - PN002
2PN021 - PN043
2PN081 - PN086
2PN101 - PN117
2PN131 - PN163
2PN401 - PN420
2PN431 - PN433
2PN451 - PN456
2PN471 - PN474
2PN481
2PN491 - PN493
2PN501 - PN502
2PN511 - PN512
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GroupVariable Number
2PN521
2PY022
1PY031
2PY036 - PY037
2PY046 - PY048
2PY051 - PY053
2PY056 - PY057
2PY101 - PY103
2PY111 - PY113
2PY131 - PY135
2PY141 - PY143
2PY151 - PY154
2PY156 - PY157
2PY161 - PY162
2PY166
2PY191
2PY201
2PY221 - PY222
2PY231
2PY241 - PY244
2PY270 - PY275
2PY281
2PY286
2PY401
2PY409 - PY411
2PY421 - PY422
2PY441
2PY451
2PY461 - PY463
2PY591 - PY595
2PY611 - PY612
2PY621
2PY631
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GroupVariable Number
2PY651
2PY671 - PY672
2PY721
2PY741
2. Spares Affected
None.
B. Concurrent Requirements
None.
C. Reason
Boeing previously received a report from an 737NG operator where the failure of the aft attach lugs on
the left elevator tab control mechanism resulted in unwanted elevator freeplay vibration during flight.
Investigation revealed that the fractured aft attach lugs on the elevator tab control mechanism allowed
freeplay of the mechanism, which led to vibration of the elevator during flight. Further investigation
revealed that the bearings installed in the elevator tab control mechanism aft attach lugs were likely
insufficiently swaged and became loose. 737NG service bulletin 737-27A1297 was issued to do a
detailed inspection for looseness of these bearings. This service bulletin does inspection of these
bearings for looseness similar to the inspections in 737-27A1297. Although the previously mentioned
incident occurred on a 737NG, the design of the bearing lug retention is essentially the same as newer
737-200's which all have the 65-45190-7 & -8 Tab Control Mechanism installation. A loose bearing in
the aft lug of the elevator tab control mechanism could lead to unwanted elevator tab freeplay and then
tab vibration which could lead to structural failure of the elevator or the horizontal stabilizer which can
result in unsafe flight conditions.
This bulletin will ensure the integrity of bearing swages, whether performed in production or during any
subsequent maintenance work done by an airline. This inspection was determined to be needed for
the 737-200 because the design of the 737-200 bearing retention is essentially the same as for the
737NG. The 737NG event showed that the design used on both the 737-200 and the 737NG using the
specification for installing the swage (BAC5435) may not be adequate.
The related Elevator Tab service bulletin is 737-27A1297.
D. Description
Group 1:
Contact Boeing to get instructions for inspection, change and/or repair for this service bulletin, and do
the work instructed by Boeing.
Group 2:
Remove access panels to gain access to the elevator tab control mechanism (mechanism) and do a
detailed inspection of the aft attach lugs (lugs). Look for rotation of the spacer. Also, use a feeler gage
to check for any gaps at certain locations. If there is a gap or a loose spacer, then replace the mechanism
per the AMM and this SB. If there is no gap or a loose spacer, then return the airplane to a serviceable
condition.
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Do repeat inspections of the mechanism at the times shown in paragraph 1.E., compliance.
The work in this service bulletin is done in the maintenance zone(s) given below.
Affected Maintenance Zones
ZoneModel
7-9, 7-10, 7-11, 7-12737-200, 737-200C
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.
Table 1: ELEVATOR TAB CONTROL MECHANISM INSPECTION - LEFT SIDE
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Within 1,500 Flight Cycles or
2,000 Flight Hours, whichever oc-
curs first, after the original issue
date of this service bulletin.
Contact Boeing to get in-
structions for inspection,
change and/or repair for
this service bulletin, and
do the work instructed by
Boeing in accordance
with Part 1, Step 1 of
paragraph 3.B., Work In-
structions.
Group 1
1,500 Flight Cycles
or 2,000 Flight
Hours, whichever
occurs first.
Within 1,500 Flight Cycles or
2,000 Flight Hours, whichever oc-
curs first, after the original issue
date of this service bulletin.
Do a detailed inspection
of the elevator tab control
mechanism in accor-
dance with Part 2, Step 2
of paragraph 3.B., Work
Instructions.
Group 2
-Before further flightReplace the elevator tab
control mechanism and
do detailed inspection
before and after installing
it, in accordance with Part
2, Step 7 of paragraph
3.B., Work Instructions.
Group 2:
Elevator tab control mecha-
nism is found to be dis-
crepant.
OR
Replacement elevator tab
control mechanism is found
to be discrepant.
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Table 2: ELEVATOR TAB CONTROL MECHANISM INSPECTION - RIGHT SIDE
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Within 1,500 Flight Cycles or
2,000 Flight Hours, whichever oc-
curs first, after the original issue
date of this service bulletin .
Contact Boeing to get in-
structions for inspection,
change and/or repair for
this service bulletin, and
do the work instructed by
Boeing in accordance
with Part 1, Step 1 of
paragraph 3.B., Work In-
structions.
Group 1
1,500 Flight Cycles
or 2,000 Flight
Hours whichever
occurs first.
Within 1,500 Flight Cycles or
2,000 Flight Hours, whichever oc-
curs first, after the original issue
date of this service bulletin .
Do a detailed inspection
of the elevator tab control
mechanism in accor-
dance with Part 2, Step 5
of paragraph 3.B., Work
Instructions.
Group 2
-Before further flightReplace the elevator tab
control mechanism and
do detailed inspection
before and after installing
it, in accordance with Part
2, Step 8 of paragraph
3.B., Work Instructions.
Group 2:
Elevator tab control mecha-
nism is found to be dis-
crepant
OR
Replacement elevator tab
control mechanism is found
to be discrepant.
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 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
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 Time to inspect the work
 Time to cure the materials
 Time to make the parts
 Time to find the tools.
INSPECT LEFT SIDE
Elapsed HoursTask HoursNumber of PersonsTask
1.001.001Open Access
0.750.751Figure 1
0.75.0.751Figure 2
1.001.001Close Access
3.503.50TOTAL FOR EACH AIR-
PLANE
INSPECT RIGHT SIDE
Elapsed HoursTask HoursNumber of PersonsTask
1.001.001Open Access
0.750.751Figure 3
0.750.751Figure 4
1.001.001Close Access
3.503.50TOTAL FOR EACH AIR-
PLANE
REPLACE MECHANISM LEFT SIDE
Elapsed HoursTask HoursNumber of PersonsTask
1.501.501Remove Mechanism
0.750.751Figure 1
0.750.751Figure 2
1.501.501Install Mechanism
1.501.501Inspect, Figures 1 & 2
1.002.002Functional Test
(a)(a)2Flight Test
7.008.00TOTAL FOR EACH AIR-
PLANE
(a) Flight test hours not included in estimate.
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REPLACE MECHANISM RIGHT SIDE
Elapsed HoursTask HoursNumber of PersonsTask
1.501.501Remove Mechanism
0.750.751Figure 3
0.750.751Figure 4
1.501.501Install Mechanism
1.501.501Inspect, Figures 3 & 4
1.002.002Functional Test
(a)(a)2Flight Test
7.008.00TOTAL FOR EACH AIR-
PLANE
(a) Flight test hours not included in estimate.
H. Weight and Balance Changes
None.
I. Electrical Load Data
Not changed.
J. References
1. Existing Data
a. Boeing Service Bulletin 737-27A1297
b. Standard Wiring Practices Manual (SWPM) SWPM 20-10-11, SWPM 20-10-12, SWPM
20-10-19
c. 737-200 Aircraft Maintenance Manual (AMM) 737-100/200 AMM 12-31-81, 737-100/200 AMM
27-31-00, 737-100/200 AMM 27-31-121
2. Data supplied with this Service Bulletin
None.
3. Installation Drawings Used in the Preparation of this Service Bulletin
None.
K. Publications Affected
1. Publications:
None.
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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
None.
B. Industry Support Information
Boeing warranty remedies are not available for the inspection, and/or repair procedures given in this
service bulletin.
C. Parts Necessary For Each Airplane
1. Kits/Parts
None.
2. Parts and Materials Supplied by the Operator
NotesExisting Part NumberNameQTYPart Number /
Specification
This part is
only neces-
sary if the El-
evator Tab
Control
Mechanism
is found dis-
crepant.
65-45190-7, -8 InstallationElevator Tab Control Mechanism165-79425-2 or -3 or
-4 or -5 or -6 As-
sembly
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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.
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### Page 23

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 limits to tighten nuts and bolts are in SRM Chapter 51
4. Use the approved fastener and process 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.
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.
8. A Detailed Inspection 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.
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9. A General Visual Inspection is defined as: A visual examination of an interior or
exterior area, installation or assembly to detect obvious damage, failure or irregularity.
This level of inspection is made from within touching distance unless otherwise
specified. A mirror may be necessary to enhance visual access to all exposed surfaces
in the inspection area. This level of inspection is made under normally available
lighting conditions such as daylight, hangar lighting, flashlight or drop-light and may
require removal or opening of access panels or doors. Stands, ladders or platforms
may be required to gain proximity to the area being checked.
10. 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.
11. Boeing Service Letter , 737-SL-51-042, Damage Reporting and Repair Plan/Design
Guidelines, is an acceptable procedure to request information from Boeing for
additional structural repair instructions. The Service Letter describes what information
must be provided to Boeing before a structural repair can be provided.
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. This service bulletin includes functional test procedures for the systems changed by
this service bulletin. More functional tests can possibly be necessary in accordance
with standard maintenance practices because of interruption to other airplane systems.
16. Some Boeing parts are supplied in a temporary configuration. Those parts are
identified with a 'U', 'W', or 'Y' in place of the '-' (dash) in the part number. It is
permitted to install parts identified with a 'U', 'W', or 'Y' as an alternative to the '-'
(dash) part number. Boeing Drawing 005W0900 contains more data.
17. Shaded areas in Figures are reference only. Shaded areas in Figures may look
different than your airplane.
B. WORK INSTRUCTIONS
Part 1 Group 1 airplanes
1. Contact Boeing to get instructions for inspection, change and/or repair for this service bulletin, and
do the work instructed by Boeing.
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Part 2 Group 2 airplanes
1. OPEN ACCESS - LEFT SIDE:
a. Gain access as required. Refer to 737-100/200 AMM 12-31-81 and 737-100/200 AMM
27-31-121 as an accepted procedure.
2. DETAILED INSPECTION - LEFT SIDE:
a. For the inboard aft attach lug of the elevator tab control mechanism (mechanism), use a feeler
gage and finger pressure to do a detailed inspection in accordance with Figure 1 and determine
if the elevator tab control mechanism is discrepant. While doing the inspection, apply inboard
and outboard hand pressure to the elevator tab control mechanism in accordance with Figure
1.
For the outboard aft attach lug of the elevator tab control mechanism, use a feeler gage and
finger pressure to do a detailed inspection in accordance with Figure 2 and determine if the
elevator tab control mechanism is discrepant. While doing the inspection, apply inboard and
outboard hand pressure to the elevator tab control mechanism in accordance with Figure 2.
(1) Spacer: If the spacer moves or rotates, then the mechanism is discrepant
(2) Lug to Spacer interface: Make sure that there is no gap between the inner face of the aft
attach lug and the spacer such that a 0.010 inch feeler gage can be inserted more than
0.16 inch. If there is such a gap, then the elevator tab control mechanism is discrepant.
b. If the elevator tab control mechanism is discrepant, then replace it in accordance with Step
3.B.7.
3. CLOSE ACCESS - LEFT SIDE:
a. Close access as required. Refer to 737-100/200 AMM 12-31-81 and 737-100/200 AMM
27-31-121 as an accepted procedure.
4. OPEN ACCESS - RIGHT SIDE
a. Gain access as required. Refer to 737-100/200 AMM 12-31-81 and 737-100/200 AMM
27-31-121 as an accepted procedure.
5. DETAILED INSPECTION - RIGHT SIDE:
a. For the inboard aft attach lug of the elevator tab control mechanism (mechanism), use a feeler
gage and finger pressure to do a detailed inspection in accordance with Figure 3 and determine
if the elevator tab control mechanism is discrepant. While doing the inspection, apply inboard
and outboard hand pressure to the elevator tab control mechanism in accordance with Figure
3.
For the outboard aft attach lug of the elevator tab control mechanism, use a feeler gage and
finger pressure to do a detailed inspection in accordance with Figure 4 and determine if the
elevator tab control mechanism is discrepant. While doing the inspection, apply inboard and
outboard hand pressure to the elevator tab control mechanism in accordance with Figure 4.
(1) Spacer: If the spacer moves or rotates, then the mechanism is discrepant
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(2) Lug to Spacer interface: Make sure that there is no gap between the inner face of the aft
attach lug and the spacer such that a 0.010 inch feeler gage can be inserted more than
0.16 inch. If there is such a gap, then the elevator tab control mechanism is discrepant.
b. If the elevator tab control mechanism is discrepant, then replace it in accordance with Step
3.B.8.
6. CLOSE ACCESS - RIGHT SIDE
a. Close access as required. Refer to 737-100/200 AMM 12-31-81 and 737-100/200 AMM
27-31-121 as an accepted procedure.
7. REPLACEMENT OF A MECHANISM- LEFT SIDE
WARNING: WHEN INSTALLING THE PINS TO CONNECT THE ELEVATOR TAB CONTROL
MECHANISM TO THE ELEVATOR, MAKE SURE YOU DON'T DAMAGE THE LUGS
OR THE BEARINGS. IF A LUG OR BEARING IS DAMAGED, THEN IT COULD
LEAD TO UNWANTED ELEVATOR TAB FREEPLAY AND THEN ELEVATOR TAB
VIBRATION WHICH COULD LEAD TO STRUCTURAL FAILURE OF THE
ELEVATOR OR THE HORIZONTAL STABILIZER.
a. Gain access as required and remove the elevator tab control mechanism (mechanism). Refer
to 737-100/200 AMM 12-31-81 and 737-100/200 AMM 27-31-121 as an accepted procedure.
b. Replace the elevator tab control mechanism as follows:
(1) Before you install the replacement mechanism, do the following inspection:
(a) For the inboard attach lug of the elevator tab control mechanism, use a feeler gage
and finger pressure to do a detailed inspection in accordance with Figure 1, except
as noted below, and determine if the replacement mechanism is discrepant.
For the outboard attach lug of the elevator tab control mechanism, use a feeler gage
and finger pressure to do a detailed inspection in accordance with Figure 2, except
as noted below, and determine if the replacement mechanism is discrepant.
NOTE: Figures 1 and 2 show the detailed inspection being done on an elevator
tab control mechanism that is installed. If a replacement mechanism is being
inspected before it is installed, then:
– Do not apply force as shown in the figures or as discussed in the figure
notes,
– These figures will not show what the mechanic will see when doing the
inspection, but this is OK.
1) Spacer: If the spacer moves or rotates, then the replacement mechanism is
discrepant
2) Lug to Spacer interface: Make sure that there is no gap between the inner face
of the aft attach lug and the spacer such that a 0.010 inch feeler gage can be
inserted more than 0.16 inch. If there is such a gap, then the replacement
mechanism is discrepant.
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(b) If the replacement mechanism is discrepant, then it cannot be installed.
(2) Install the replacement mechanism. Refer to 737-100/200 AMM 27-31-121 as an accepted
procedure.
(3) After you install the replacement mechanism, do a detailed inspection of the elevator tab
control mechanism in accordance with Step 3.B.2.
c. Close access as required. Refer to 737-100/200 AMM 12-31-81 and 737-100/200 AMM
27-31-121 as an accepted procedure.
d. Functional tests and (Manual mode and Power Mode) flight test of the airplane are required
when an elevator tab control mechanism is replaced. Refer to 737-100/200 AMM 27-31-00
as an accepted procedure.
8. REPLACEMENT OF A MECHANISM - RIGHT SIDE
WARNING: WHEN INSTALLING THE PINS TO CONNECT THE ELEVATOR TAB CONTROL
MECHANISM TO THE ELEVATOR, MAKE SURE YOU DON'T DAMAGE THE LUGS
OR THE BEARINGS. IF A LUG OR BEARING IS DAMAGED, THEN IT COULD
LEAD TO UNWANTED ELEVATOR TAB FREEPLAY AND THEN ELEVATOR TAB
VIBRATION WHICH COULD LEAD TO STRUCTURAL FAILURE OF THE
ELEVATOR OR THE HORIZONTAL STABILIZER.
a. Gain access as required and remove the elevator tab control mechanism (mechanism). Refer
to 737-100/200 AMM 12-31-81 and 737-100/200 AMM 27-31-121 as an accepted procedure.
b. Replace the elevator tab control mechanism as follows:
(1) Before you install the replacement mechanism, do the following inspection:
(a) For the inboard attach lug of the elevator tab control mechanism, use a feeler gage
and finger pressure to do a detailed inspection in accordance with Figure 3, except
as noted below, and determine if the replacement mechanism is discrepant.
For the outboard attach lug of the elevator tab control mechanism, use a feeler gage
and finger pressure to do a detailed inspection in accordance with Figure 4, except
as noted below, and determine if the replacement mechanism is discrepant.
NOTE: Figures 3 and 4 show the detailed inspection being done on an elevator
tab control mechanism that is installed. If a replacement mechanism is being
inspected before it is installed, then:
– Do not apply force as shown in the figures or as discussed in the figure
notes,
– These figures will not show what the mechanic will see when doing the
inspection, but this is OK.
1) Spacer: If the spacer moves or rotates, then the replacement mechanism is
discrepant
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2) Lug to Spacer interface: Make sure that there is no gap between the inner face
of the aft attach lug and the spacer such that a 0.010 inch feeler gage can be
inserted more than 0.16 inch. If there is such a gap, then the replacement
mechanism is discrepant.
(b) If the replacement mechanism is discrepant, then it cannot be installed.
(2) Install the replacement mechanism. Refer to 737-100/200 AMM 27-31-121 as an accepted
procedure.
(3) After you install the replacement mechanism, do a detailed inspection of the elevator tab
control mechanism in accordance with Step 3.B.5.
c. Close access as required. Refer to 737-100/200 AMM 12-31-81 and 737-100/200 AMM
27-31-121 as an accepted procedure.
d. Functional tests (Manual mode and Power Mode) flight test of the airplane are required when
an elevator tab control mechanism is replaced. Refer to 737-100/200 AMM 27-31-00 as an
accepted procedure.
9. Return the airplane to a serviceable condition.
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BOEING SERVICE BULLETIN 737-27A1302
ALERT  ALERT
INNER FACE OF LUG B
FWD
PANEL 9105 SHOWN REMOVED FOR CLARITY  2129610
FIGURE 1: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - LEFT SIDE
(SHEET 1 OF 4)
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### Page 30 (OCR)

BOEING SERVICE BULLETIN 737-27A1302
ALERT  ALERT
SPACER (2)
LUG/SPACER (
INTERFACE
FWD
INNER FACE OF LUG  2129611
FIGURE 1: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - LEFT SIDE
(SHEET 2 OF 4)
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### Page 31 (OCR)

BOEING SERVICE BULLETIN 737-27A1302
ALERT  ALERT
CENTER OF BEARING
USE FEELER GAGE  / BEARING  CENTER OF
WITHIN THE
APPROXIMATE
AREA SHOWN
DEPTH OF
FEELER
GAGE
SPACER
SWAGE
RING
LUG
CENTER OF FEELER GAGE
RADIAL TO CENTER OF THE
BEARING
FEELER GAGE DEPTH MEASUREMENT  2129612
FIGURE 1: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - LEFT SIDE
(SHEET 3 OF 4)
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### Page 32

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
More DataQtyIdentificationNameTaskStep
CAUTION: DO NOT APPLY FORCE WITH ANYTHING OTHER THAN YOUR HAND. DO NOT APPLY
EXCESSIVE FORCE OR YOU MAY DAMAGE THE ELEVATOR TAB CONTROL MECHANISM
LUGS OR BEARINGS. A BENT LUG OR LOOSE BEARING COULD LEAD TO UNWANTED
ELEVATOR TAB FREEPLAY AND THEN TAB VIBRATION WHICH COULD LEAD TO
STRUCTURAL FAILURE OF THE ELEVATOR OR THE HORIZONTAL STABILIZER.
Using hand pres-
sure, apply force to
the mechanism alter-
nating between the
inboard and out-
board direction while
doing the inspec-
tions in the following
steps. The force can
be applied at any lo-
cation on the mecha-
nism, but no more
than four inches for-
ward of the elevator
front spar.
--forceApply1
(a)1-spacerInspect2
(b) If there is sealant
in the interface, do
not remove it.
1-lug/spacer interfaceInspect3
(a) As you apply force to the mechanism alternating between the inboard and outboard direction, use finger
pressure and try to rotate the spacer.
(b) Using a feeler gage, Make sure that there is no gap between the inner face of the lug and the spacer
such that a 0.010 inch feeler gage can be inserted more than 0.16 inch. Do the inspection at a single lo-
cation between the allowable outer limits defined in Detail C. Apply force to the mechanism alternating
between the inboard and outboard direction as you use the feeler gage.
FIGURE 1: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - LEFT SIDE
(SHEET 4 OF 4)
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BOEING SERVICE BULLETIN 737-27A1302
ALERT  ALERT
FWD
PANEL 9105 SHOWN REMOVED FOR CLARITY  2129613
FIGURE 2: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - LEFT SIDE
(SHEET 1 OF 4)
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### Page 34 (OCR)

BOEING SERVICE BULLETIN 737-27A1302
ALERT  ALERT
(2) SPACER
FWD  LUG/SPACER
INTERFACE
INNER FACE OF LUG  2129614
FIGURE 2: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - LEFT SIDE
(SHEET 2 OF 4)
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### Page 35 (OCR)

BOEING SERVICE BULLETIN 737-27A1302
ALERT  ALERT
CENTER OF BEARING
USE FEELER GAGE  / BEARING  CENTER OF
WITHIN THE
APPROXIMATE
AREA SHOWN
DEPTH OF
FEELER
GAGE
SPACER
SWAGE
RING
LUG
CENTER OF FEELER GAGE
RADIAL TO CENTER OF THE
BEARING
FEELER GAGE DEPTH MEASUREMENT  2129616
FIGURE 2: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - LEFT SIDE
(SHEET 3 OF 4)
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737-27A1302
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### Page 36

The step numbers shown below agree with the numbers shown in the circle symbols in the figure
More DataQtyIdentificationNameTaskStep
CAUTION: DO NOT APPLY FORCE WITH ANYTHING OTHER THAN YOUR HAND. DO NOT APPLY
EXCESSIVE FORCE OR YOU MAY DAMAGE THE ELEVATOR TAB CONTROL MECHANISM
LUGS OR BEARINGS. A BENT LUG OR LOOSE BEARING COULD LEAD TO UNWANTED
ELEVATOR TAB FREEPLAY AND THEN TAB VIBRATION WHICH COULD LEAD TO
STRUCTURAL FAILURE OF THE ELEVATOR OR THE HORIZONTAL STABILIZER.
Using hand pres-
sure, apply force to
the mechanism alter-
nating between the
inboard and out-
board direction while
doing the inspec-
tions in the following
steps. The force can
be applied at any lo-
cation on the mecha-
nism, but no more
than four inches for-
ward of the elevator
front spar.
--forceApply1
(a)1-spacerInspect2
(b) If there is sealant
in the interface, do
not remove it.
1-lug/spacer interfaceInspect3
(a) As you apply force to the mechanism alternating between the inboard and outboard direction, use finger
pressure and try to rotate the spacer.
(b) Using a feeler gage, Make sure that there is no gap between the inner face of the lug and the spacer
such that a 0.010 inch feeler gage can be inserted more than 0.16 inch. Do the inspection at a single lo-
cation between the allowable outer limits defined in Detail C. Apply force to the mechanism alternating
between the inboard and outboard direction as you use the feeler gage.
FIGURE 2: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - LEFT SIDE
(SHEET 4 OF 4)
BOEING PROPRIETARY -
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### Page 37 (OCR)

BOEING SERVICE BULLETIN 737-27A1302
ALERT  ALERT
B INNER FACE OF LUG
FWD
PANEL 9205 SHOWN REMOVED FOR CLARITY  2129617
FIGURE 3: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - RIGHT SIDE
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### Page 38 (OCR)

BOEING SERVICE BULLETIN 737-27A1302
ALERT  ALERT
(2) SPACER
3) LUG/SPACE  INTERFAC
C
FWD
INNER FACE OF LUG  2129619
FIGURE 3: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - RIGHT SIDE
(SHEET 2 OF 4)
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### Page 39 (OCR)

BOEING SERVICE BULLETIN 737-27A1302
ALERT  ALERT
CENTER OF BEARING
BEARING  CENTER OF  • USE FEELER GAGE
WITHIN THE
APPROXIMATE
AREA SHOWN
DEPTH OF
FEELER
GAGE
SPACER
SWAGE
RING
_ LUG
CENTER OF FEELER GAGE
RADIAL TO CENTER OF THE
FEELER GAGE DEPTH MEASUREMENT  2129620
FIGURE 3: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - RIGHT SIDE
Original Issue: April 24, 2012
737-27A1302
Copyright © Unpublished Work - See page 1 for details.  39 of 44

### Page 40

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
More DataQtyIdentificationNameTaskStep
CAUTION: DO NOT APPLY FORCE WITH ANYTHING OTHER THAN YOUR HAND. DO NOT APPLY
EXCESSIVE FORCE OR YOU MAY DAMAGE THE ELEVATOR TAB CONTROL MECHANISM
LUGS OR BEARINGS. A BENT LUG OR LOOSE BEARING COULD LEAD TO UNWANTED
ELEVATOR TAB FREEPLAY AND THEN TAB VIBRATION WHICH COULD LEAD TO
STRUCTURAL FAILURE OF THE ELEVATOR OR THE HORIZONTAL STABILIZER.
Using hand pres-
sure, apply force to
the mechanism alter-
nating between the
inboard and out-
board direction while
doing the inspec-
tions in the following
steps. The force can
be applied at any lo-
cation on the mecha-
nism, but no more
than four inches for-
ward of the elevator
front spar.
--forceApply1
(a)1-spacerInspect2
(b) If there is sealant
in the interface, do
not remove it.
1-lug/spacer interfaceInspect3
(a) As you apply force to the mechanism alternating between the inboard and outboard direction, use finger
pressure and try to rotate the spacer.
(b) Using a feeler gage, Make sure that there is no gap between the inner face of the lug and the spacer
such that a 0.010 inch feeler gage can be inserted more than 0.16 inch. Do the inspection at a single lo-
cation between the allowable outer limits defined in Detail C. Apply force to the mechanism alternating
between the inboard and outboard direction as you use the feeler gage.
FIGURE 3: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - RIGHT SIDE
(SHEET 4 OF 4)
BOEING PROPRIETARY -
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Original Issue: April 24, 2012
737-27A1302
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BOEING SERVICE BULLETIN 737-27A1302
ALERTALERT

### Page 41 (OCR)

BOEING SERVICE BULLETIN 737-27A1302
ALERT  ALERT
INNER FACE OF LUG  B
FWD
PANEL 9205 SHOWN REMOVED FOR CLARITY  2129621
FIGURE 4: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - RIGHT SIDE
(SHEET 1 OF 4)
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### Page 42 (OCR)

BOEING SERVICE BULLETIN 737-27A1302
ALERT  ALERT
SPACER 2
LUG/SPACER (
INTERFACE
FWD
INNER FACE OF LUG  2129622
FIGURE 4: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - RIGHT SIDE
(SHEET 2 OF 4)
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737-27A1302
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### Page 43 (OCR)

BOEING SERVICE BULLETIN 737-27A1302
ALERT  ALERT
CENTER OF BEARING
BEARING  CENTER OF  • USE FEELER GAGE
WITHIN THE
APPROXIMATE
AREA SHOWN
DEPTH OF
FEELER
GAGE
SPACER
SWAGE
RING
_ LUG
CENTER OF FEELER GAGE
RADIAL TO CENTER OF THẺ
BEARING
FEELER GAGE DEPTH MEASUREMENT  2129624
FIGURE 4: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - RIGHT SIDE
(SHEET 3 OF 4)
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737-27A1302
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### Page 44

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
More DataQtyIdentificationNameTaskStep
CAUTION: DO NOT APPLY FORCE WITH ANYTHING OTHER THAN YOUR HAND. DO NOT APPLY
EXCESSIVE FORCE OR YOU MAY DAMAGE THE ELEVATOR TAB CONTROL MECHANISM
LUGS OR BEARINGS. A BENT LUG OR LOOSE BEARING COULD LEAD TO UNWANTED
ELEVATOR TAB FREEPLAY AND THEN TAB VIBRATION WHICH COULD LEAD TO
STRUCTURAL FAILURE OF THE ELEVATOR OR THE HORIZONTAL STABILIZER.
Using hand pres-
sure, apply force to
the mechanism alter-
nating between the
inboard and out-
board direction while
doing the inspec-
tions in the following
steps. The force can
be applied at any lo-
cation on the mecha-
nism, but no more
than four inches for-
ward of the elevator
front spar.
--forceApply1
(a)1-spacerInspect2
(b) If there is sealant
in the interface, do
not remove it.
1-lug/spacer interfaceInspect3
(a) As you apply force to the mechanism alternating between the inboard and outboard direction, use finger
pressure and try to rotate the spacer.
(b) Using a feeler gage, Make sure that there is no gap between the inner face of the lug and the spacer
such that a 0.010 inch feeler gage can be inserted more than 0.16 inch. Do the inspection at a single lo-
cation between the allowable outer limits defined in Detail C. Apply force to the mechanism alternating
between the inboard and outboard direction as you use the feeler gage.
FIGURE 4: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - RIGHT SIDE
(SHEET 4 OF 4)
BOEING PROPRIETARY -
Copyright © Unpublished Work - See page 1 for details.
Original Issue: April 24, 2012
737-27A1302
44 of 44
BOEING SERVICE BULLETIN 737-27A1302
ALERTALERT

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