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

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ECCN: 9E991

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3.0
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BLANK PAGE
Table of Contents

Summary ...................................................... 5

1. PLANNING INFORMATION ........................................ 9

A. Effectivity ................................................ 9

1. Airplanes ............................................. 9

2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

E. Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

1. Existing Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

2. Data supplied with this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3. Installation Drawings Used in the Preparation of this Service Bulletin . . . . . . . . . . . . 18

K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

A. Material - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

C. Parts Necessary For Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

1. Kits/Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2. Parts and Materials Supplied by the Operator . . . . . . . . . . . . . . . . . . . . . . . . 21

3. Parts Modified and Reidentified . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4. Parts Removed and Not Replaced . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

E. Special Tooling - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . 21

3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

FIGURE 1: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - LEFT SIDE . . . . . . . 29

FIGURE 2: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - LEFT SIDE . . . . . . 33

FIGURE 3: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - RIGHT SIDE . . . . . . 37

FIGURE 4: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - RIGHT SIDE . . . . . 41

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BLANK PAGE
Commercial 

Airplanes 737

Service Bulletin

ALERT

Summary 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.

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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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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BLANK PAGE
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

GROUP CONFIGURATION DESCRIPTION

1 - 737-200, 200C Airplanes Line Number 288 to 291; Contact Boeing

2 - 737-200, 200C Airplanes Line Number 292 to 1585

Airplane Models:

737-200, 737-200C

Variable Number Group

PG584 - PG586 2

PH001 2

PH011 - PH013 2

PH021 - PH024 2

PH742 1

PH743 2

PJ003 - PJ009 2

PJ105 - PJ119 2

PJ201 - PJ219 2

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Variable Number Group

PK026 - PK029 2

PK041 - PK053 2

PK061 - PK070 2

PK081 - PK082 2

PK091 - PK099 2

PK101 - PK103 2

PK111 - PK120 2

PK141 - PK146 2

PK201 - PK204 2

PK211 - PK223 2

PK231 - PK241 2

PK251 - PK258 2

PK271 - PK274 2

PK281 - PK289 2

PK291 2

PK301 - PK318 2

PK341 2

PK351 - PK361 2

PK391 2

PK431 - PK433 2

PK451 - PK452 2

PK461 - PK469 2

PK495 2

PK501 - PK504 2

PK511 - PK515 2

PK519 2

PK521 - PK528 2

PK541 - PK565 2

PK581 2

PK591 - PK599 2

PK601 - PK617 2

PK621 - PK637 2

PK641 - PK642 2

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Variable Number Group

PK661 - PK666 2

PK671 - PK681 2

PK691 - PK697 2

PK711 - PK716 2

PK731 - PK765 2

PK771 - PK779 2

PK801 - PK804 2

PK819 - PK827 2

PK830 2

PK861 - PK863 2

PK871 - PK874 2

PK881 - PK884 2

PK901 - PK938 2

PK971 - PK974 2

PL001 - PL028 2

PL061 2

PL081 2

PL101 - PL113 2

PL151 2

PL171 - PL172 2

PL201 - PL203 2

PL221 2

PL401 - PL417 2

PL421 2

PL441 2

PL451 - PL456 2

PL471 2

PL491 2

PL501 - PL506 2

PL551 - PL562 2

PL581 2

PL601 - PL603 2

PL611 2

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Variable Number Group

PL621 - PL626 2

PL631 - PL632 2

PL712 1

PL716 1

PL717 - PL747 2

PL756 2

PL758 2

PL761 - PL770 2

PL781 - PL788 2

PL793 2

PM001 - PM006 2

PM016 - PM017 2

PM021 - PM023 2

PM051 - PM066 2

PM101 - PM119 2

PM141 - PM142 2

PM171 2

PM181 2

PM251 - PM255 2

PM281 - PM283 2

PN001 - PN002 2

PN021 - PN043 2

PN081 - PN086 2

PN101 - PN117 2

PN131 - PN163 2

PN401 - PN420 2

PN431 - PN433 2

PN451 - PN456 2

PN471 - PN474 2

PN481 2

PN491 - PN493 2

PN501 - PN502 2

PN511 - PN512 2

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BOEING SERVICE BULLETIN 737-27A1302

ALERT ALERT
Variable Number Group

PN521 2

PY022 2

PY031 1

PY036 - PY037 2

PY046 - PY048 2

PY051 - PY053 2

PY056 - PY057 2

PY101 - PY103 2

PY111 - PY113 2

PY131 - PY135 2

PY141 - PY143 2

PY151 - PY154 2

PY156 - PY157 2

PY161 - PY162 2

PY166 2

PY191 2

PY201 2

PY221 - PY222 2

PY231 2

PY241 - PY244 2

PY270 - PY275 2

PY281 2

PY286 2

PY401 2

PY409 - PY411 2

PY421 - PY422 2

PY441 2

PY451 2

PY461 - PY463 2

PY591 - PY595 2

PY611 - PY612 2

PY621 2

PY631 2

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Variable Number Group

PY651 2

PY671 - PY672 2

PY721 2

PY741 2

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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BOEING SERVICE BULLETIN 737-27A1302

ALERT ALERT
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

Model Zone

737-200, 737-200C 7-9, 7-10, 7-11, 7-12

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)

Condition Action Compliance Time

Within 1,500 Flight Cycles or -

2,000 Flight Hours, whichever occurs first, after the original issue

date of this service bulletin.

Contact Boeing to get instructions 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 Instructions.

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 occurs first, after the original issue

date of this service bulletin.

Do a detailed inspection

of the elevator tab control

mechanism in accordance with Part 2, Step 2

of paragraph 3.B., Work

Instructions.

Group 2

Replace the elevator tab Before further flight -

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 mechanism is found to be discrepant.

OR

Replacement elevator tab

control mechanism is found

to be discrepant.

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BOEING SERVICE BULLETIN 737-27A1302

ALERT ALERT
Table 2: ELEVATOR TAB CONTROL MECHANISM INSPECTION - RIGHT SIDE

Repeat Interval

(Not to Exceed)

Condition Action Compliance Time

Within 1,500 Flight Cycles or -

2,000 Flight Hours, whichever occurs first, after the original issue

date of this service bulletin .

Contact Boeing to get instructions 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 Instructions.

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 occurs first, after the original issue

date of this service bulletin .

Do a detailed inspection

of the elevator tab control

mechanism in accordance with Part 2, Step 5

of paragraph 3.B., Work

Instructions.

Group 2

Replace the elevator tab Before further flight -

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 mechanism is found to be discrepant

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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BOEING SERVICE BULLETIN 737-27A1302

ALERT ALERT
• Time to inspect the work

• Time to cure the materials

• Time to make the parts

• Time to find the tools.

INSPECT LEFT SIDE

Task Number of Persons Task Hours Elapsed Hours

Open Access 1 1.00 1.00

Figure 1 1 0.75 0.75

Figure 2 1 .0.75 0.75

Close Access 1 1.00 1.00

TOTAL FOR EACH AIR- 3.50 3.50

PLANE

INSPECT RIGHT SIDE

Task Number of Persons Task Hours Elapsed Hours

Open Access 1 1.00 1.00

Figure 3 1 0.75 0.75

Figure 4 1 0.75 0.75

Close Access 1 1.00 1.00

TOTAL FOR EACH AIR- 3.50 3.50

PLANE

REPLACE MECHANISM LEFT SIDE

Task Number of Persons Task Hours Elapsed Hours

Remove Mechanism 1 1.50 1.50

Figure 1 1 0.75 0.75

Figure 2 1 0.75 0.75

Install Mechanism 1 1.50 1.50

Inspect, Figures 1 & 2 1 1.50 1.50

Functional Test 2 2.00 1.00

Flight Test 2 (a) (a)

TOTAL FOR EACH AIR- 8.00 7.00

PLANE

(a) Flight test hours not included in estimate.

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ALERT ALERT
REPLACE MECHANISM RIGHT SIDE

Task Number of Persons Task Hours Elapsed Hours

Remove Mechanism 1 1.50 1.50

Figure 3 1 0.75 0.75

Figure 4 1 0.75 0.75

Install Mechanism 1 1.50 1.50

Inspect, Figures 3 & 4 1 1.50 1.50

Functional Test 2 2.00 1.00

Flight Test 2 (a) (a)

TOTAL FOR EACH AIR- 8.00 7.00

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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BOEING SERVICE BULLETIN 737-27A1302

ALERT ALERT
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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BLANK PAGE
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

Part Number / QTY Name Existing Part Number Notes

Specification

This part is

only necessary if the Elevator Tab

Control

Mechanism

is found discrepant.

65-79425-2 or -3 or 1 Elevator Tab Control Mechanism 65-45190-7, -8 Installation

-4 or -5 or -6 Assembly

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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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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FIGURE 1: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - LEFT SIDE

(SHEET 1 OF 4)

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FIGURE 1: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - LEFT SIDE

(SHEET 2 OF 4)

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FIGURE 1: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - LEFT SIDE

(SHEET 3 OF 4)

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The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

Step Task Name Identification Qty More Data

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 pressure, apply force to

the mechanism alternating between the

inboard and outboard direction while

doing the inspections in the following

steps. The force can

be applied at any location on the mechanism, but no more

than four inches forward of the elevator

front spar.

1 Apply force - -

2 Inspect spacer - 1 (a)

(b) If there is sealant

in the interface, do

not remove it.

3 Inspect lug/spacer interface - 1

(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 location 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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FIGURE 2: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - LEFT SIDE

(SHEET 1 OF 4)

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FIGURE 2: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - LEFT SIDE

(SHEET 2 OF 4)

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FIGURE 2: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - LEFT SIDE

(SHEET 3 OF 4)

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ALERT ALERT
The step numbers shown below agree with the numbers shown in the circle symbols in the figure

Step Task Name Identification Qty More Data

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 pressure, apply force to

the mechanism alternating between the

inboard and outboard direction while

doing the inspections in the following

steps. The force can

be applied at any location on the mechanism, but no more

than four inches forward of the elevator

front spar.

1 Apply force - -

2 Inspect spacer - 1 (a)

(b) If there is sealant

in the interface, do

not remove it.

3 Inspect lug/spacer interface - 1

(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 location 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)

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FIGURE 3: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - RIGHT SIDE

(SHEET 1 OF 4)

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FIGURE 3: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - RIGHT SIDE

(SHEET 2 OF 4)

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FIGURE 3: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - RIGHT SIDE

(SHEET 3 OF 4)

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ALERT ALERT
The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

Step Task Name Identification Qty More Data

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 pressure, apply force to

the mechanism alternating between the

inboard and outboard direction while

doing the inspections in the following

steps. The force can

be applied at any location on the mechanism, but no more

than four inches forward of the elevator

front spar.

1 Apply force - -

2 Inspect spacer - 1 (a)

(b) If there is sealant

in the interface, do

not remove it.

3 Inspect lug/spacer interface - 1

(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 location 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)

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FIGURE 4: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - RIGHT SIDE

(SHEET 1 OF 4)

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FIGURE 4: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - RIGHT SIDE

(SHEET 2 OF 4)

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FIGURE 4: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - RIGHT SIDE

(SHEET 3 OF 4)

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ALERT ALERT
The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

Step Task Name Identification Qty More Data

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 pressure, apply force to

the mechanism alternating between the

inboard and outboard direction while

doing the inspections in the following

steps. The force can

be applied at any location on the mechanism, but no more

than four inches forward of the elevator

front spar.

1 Apply force - -

2 Inspect spacer - 1 (a)

(b) If there is sealant

in the interface, do

not remove it.

3 Inspect lug/spacer interface - 1

(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 location 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)

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