TM_M113 A2 (TM9-2350-261-24P)

This copy is a reprint which Includes TM 9-1015-200-10
current pages from Changes 1 through 4
CHECK FOR CURRENT CHANGES
REVISION
SEE PAGE i FOR DETAILS

OPERATOR’S MANUAL
FOR

MORTAR, 81-MM, M29A1
(1015-00-999-7794)

HEADQUARTERS
DEPARTMENT OF THE ARMY

OCTOBER 1985

URGENT CHANGE

CHANGE TM 9-1015-200-10
NO.5 C5

HEADQUARTERS
DEPARTMENT OF THE ARMY
Washington D.C., 15 April 1996

OPERATORS MANUAL
FOR

MORTAR, 81-MM, M29A1
(NSN 1015-01-99774)

TM 9-1015-200-10, October 1985, changed as follows::

1. Remove pages and insert new page indicated below.

2 New or changed material is indicated by vertical bar in 4e margin of the page.

Remove Pages Insert Pages

c and d c and d
i thru 1-2 i thru 1-2
2-64.1 and 2-64.2 2-64.1 and 2-64.2
4-1 and 4-2 4-1 and 4-2
4-4.1 and 4-4.2 None
4-8.1 (4-8.2 blank) None
4-10.1 thru 4-10.4 (4-10.3 blank) 4-10.4
4-13 thru 4-20 4-13 thru 4-17 (4-18 blank)
None 4-19 and 4-20
4-20.3 (4-20.4 bank) None
4-23 thru 4-26.2 4-23 thru 4-26
4-27 thru 4-34 4-27 thru 4-34
B-13 thru C-0 B-13 thru C-0
Index 1 thru Index 4 Index 1 thru Index 4
Index 7 and Index 8 Index 7 and Index 8

3. File this change sheet in the publication for reference purposes.



TM 9-1015-200-10
C4

CHANGE HEADQUARTERS
No. 4 DEPARTMENT OF THE ARMY
Washington, DC25 October 1989

Operator’s Manual
for

MORTAR, 81-MM, M29A1
(1015-00-999-7794)

TM 9-1015-200-10, October 1985, is changed as follows:

1. Remove old pages and insert new pages as indicated below.

2. New or changed material is indicated by a vertical bar in the margin of the page. Illustration changes are indicated by
a miniature pointing hand.

Remove Pages Insert Pages

c and d c and d
4-13 and 4-14 4-13 and 4-14
4-15 and 4-16 4-15 and 4-16
4-17 and 4-18 4-17 and 4-18

3. File this change sheet in back of the publication for reference purposes.

By Order of the Secretary of the Army: CARL E. VUONO
Official: General, United States Army

Chief of Staff

WILLIAM J. MEEHAN II
Brigadier General, United States Army

The Adjutant General

DISTRIBUTION:

To be distributed in accordance with DA Form 12-40, Operator’s Maintenance requirements for Mortar, 81-MM. M29,
M29A1.

* U.S. GOVERNMENT PRINTING OFFICE: 1992 311-831/44416

TM 9-1015-200-10
C3

Change HEADQUARTERS
No. 3 DEPARTMENT OF THE ARMY
Washington, D.C. 10 March 1989

Operator’s Manual
for

Mortar, 81-MM, M29A1
(1015-00-999-7794)

EMERGENCY SAFETY CHANGE

TM 9-1015-200-10, 23 October 1985, is changed as follows:

1. Remove old pages and insert new pages as indicated below:

Remove Pages Insert Pages

None c through d
iii and 1-0 iii and 1-0
2-63 and 2-64 2-63 through 2-64.2
4-1 and 4-2 4-1 and 4-2
None 4-4.1 and 4-4.2
None 4-8.1 (4-8.2 blank)

Remove Pages TM 9-1015-200-10

None Insert Pages
4-13 through 4-16
4-17 through 4-20 4-10.1 through 4-10.5 (4-10.6 blank)
None 4-13 through 4-16
(4-20.4 blank) 4-17 through 4-20
4-23 through 4-26 4-20.1 through 4-20.3
4-27 through 4-32
B-13 through C-0 4-23 through 4-26.2
D-7 through Index 10 4-27 through 4-35 (4-36 blank)
B-13 through C-0
D-7 through Index 10

2. New or changed material is indicated by a vertical bar In the margin of the page.
3. File this change sheet in back of the publication for reference purposes.

By Order of the Secretary of the Army: CARL E. VUONO
Official: General, United States Army

Chief of Staff

WILLIAM J. MEEHAN II
Brigadier General, United States Army

The Adjutant General

DISTRIBUTION:

To be distributed in accordance with DA Form 12-40, Operator Maintenance requirements for Mortar, 81M, M99,
M29A1.

Change TM 9-1015-200-10
No. 2 C2

HEADQUARTERS
DEPARTMENT OF THE ARMY
WASHINGTON, D.C. 16 September 1988

Operator’s Manual
for

Mortar, 81-MM, M29A1
(1015-00-999-7794)
URGENT CHANGE

TM 9-1015-200-10, 23 October 1985, is changed as follows:

1. Remove old pages and insert new pages as indicated below:

Remove Pages Insert Pages

a and b a and b
2-63 and 2-64 2-63 and 2-64

2. New or changed material is indicated by a vertical bar in the margin of the page.
3. File this change sheet in back of the publication for reference purposes.

By Order of the Secretary of the Army: CARL E. VUONO
General, United States Army
Official:
R. L. DILWORTH Chief of Staff

Brigadier General, United States Army
The Adjutant General

Distribution:

To be distributed in accordance with DA Form 12-40, Operator’s Maintenance requirements for Mortar, 81-MM, M29,
M23A1.

Change TM 9-1015-200-10
C1
No. 1
HEADQUARTERS
DEPARTMENT OF THE ARMY
WASHINGTON, D.C. 2 July 1987

Operator’s Manual
for

Mortar, 81-MM, M29A1
(1015-00-999-7794)

TM 9-1015-200-10, 23 October 1985, is changed as follows:

1. Remove old pages and insert new pages as indicated below:

Remove Pages Insert Pages

B-13 through C-0 B-13 through C-0

2. New or changed material is Indicated by a vertical bar in the margin of the page.
3. File this change sheet in back of the publication for reference purposes.

By Order of the Secretary of the Army:

JOHN A. WICKHAM, JR.
General, United States Army

Chief of Staff

Official:

MILDRED E. HEDBERG
Brigadier General, United States Army

The Adjutant General

Distribution:

To be distributed in accordance with DA Form 12-40, Operators Maintenance Requirements for Mortar, 81-MM, M29,
M29A1.

WARNING

• Double loading of mortar ammunition has resulted in catastrophic accidents. Loading a mortar weapon with
two men (alternately) can be very dangerous and could prove fatal. Even with one-man loading, double
loading can occur. This is especially true in rapid fire exercises. For this reason, it is imperative that there be
absolute certainty that the previous round left the mortar tube before a new round is dropped in.

• Upon releasing cartridge, pass hands downward and, at the same time, turn away from muzzle of mortar
cannon to avoid blast which occurs when cartridge fires.

• Do not try to force a cartridge down mortar cannon.

• If misfire procedure does not cause the cartridge to fire and mortar is hot, wait until the mortar is cool enough
to move with bare hands, or if the mortar is cool at the time of the misfire, wait one minute before removing
the cartridge. Water or snow applied to the outside of the barrel can be used for cooling. This is to avoid an
accident from possible delayed action of the ignition cartridge.

• Under no circumstances will base cap end of cannon be lowered again below a horizontal position until
cartridge has been removed from cannon.

• Keep head and body away from the front of the mortar when removing a misfire.

Change 2 a

WARNING

• Gunner must not put his hand on the base cap when lifting and holding barrel.

• Firing site must have enough mask clearance and no overhead obstructions.

• Don't park the carrier near any overhead obstructions that would block the projectile and cause a premature
burst. You could get hurt or you could hurt other friendly troops.

• Dented barrels must be replaced as they are unsafe for firing.

• Mortar crew is required to use single hearing protection during firing.

• Dry cleaning solvents (SD) and paint thinners (TPM) are flammable. Do not clean parts near an open flame or
in a smoking area. Dry cleaning solvents and paint thinners evaporate quickly and have a drying effect on
the skin. When used without protective gloves, these chemicals may cause irritation to, or cracking of, the
skin.

• For information on first aid, see FM 21-11.

b

WARNING

ALLOWABLE NUMBER OF ROUNDS PER DAY (ANOR)*

To reduce hazards from blast overpressure during firing, the mortar crew is required to use hearing protection.
Using the proper head position and single hearing protection, the ANOR that can be fired each day are noted
below.

300 SERIES AMMUNMTON

CHARGE 301 374/375

4 50 **
8 143 -
9 - 125

*For training only, does not apply In combat.

**For M374A3/M375A3 series ammunition, ANOR - 106.

Change 5 c

WARNING
No 800 series ammunition, other than M880SRTP, will be fired from the M29/M29A1 cannon.
All cartridge must be inspected for damage prior to firing. In addition, unpacked rounds which have been
subjected to rough handling must be inspected prior to firing.

Change 5 d

TECHNICAL MANUAL *TM 9-10154-200-10
No. 9-1015-200-10
HEADQUARTERS
DEPARTMENT OF THE ARMY
Washington, DC, 23 October 1985

Operator’s Manual
for

MORTAR, 81-MM, M29A1
(1015-00-999-7794)

REPORTING ERRORS AND RECOMMENDING IMPROVEMIENTS

You can help improve this manual. If you find any mistakes, or if you know of a way to improve the
procedures, please let us know. Mail your letter or DA Form 2028 (Recommended Changes to
Equipment Publications and Blank Form) direct to: Director, Armament and Chemical Acquisition and
Logistics Activity, ATTN: AMSTA-AC-MCML, Rock Island, IL 61299-7630. A reply will be furnished to
you.

*This manual supersedes as much of TM 9-1015-200-12, 12 April 1971, including all changes , as pertains to
operator and operator maintenance, and TM 9-1015-200-ESC, 20 March 1975, including all changes.

Change 5 i

Page

CHAPTER 1 INTRODUCTION................................................................................................................... 1-1

Section I. General Information .............................................................................................................. 1-1
Section II. Equipment Description .......................................................................................................... 1-3
Section III. Technical Principles of Operation ......................................................................................... 1-11

CHAPTER 2 OPERATING INSTRUCTIONS ............................................................................................. 2-0

Section I. Description and Use of Operator’s Controls and Indicators .................................................. 2-0
Section II. Preventive Maintenance Checks and Services (PMCS) ....................................................... 2-6
Section III. Operation under Usual Conditions ........................................................................................ 2-24
Section IV. Operation under Unusual Conditions .................................................................................... 2-81
Section V. Operation of 81-mm Mortar M29A1 Mounted on M125A1/A2 Carrier................................... 2-84

CHAPTER 3 MAINTENANCE INSTRUCTIONS........................................................................................ 3-0

Section I. Lubrication Instructions ......................................................................................................... 3-0
Section II. Troubleshooting Procedures ................................................................................................. 3-3
Section III. Maintenance Procedures ...................................................................................................... 3-7
Section IV. Operation and Maintenance of Auxiliary Equipment ............................................................. 3-16

CHAPTER 4 AMMUNITION ....................................................................................................................... 4-1

Section I. Authorized Cartridges............................................................................................................ 4-1
Section II. Preparation for Firing............................................................................................................. 4-13

ii

Section Page
Section
Section III. Loading and Firing.............................................................................................................. 4-15
Section IV. Unfired Cartridges .............................................................................................................. 4-15
Section V. Care and Handling of Cartridges........................................................................................ 4-16
Section VI. Fuzes.................................................................................................................................. 4-19
Section VII. Installation of Fuzes ........................................................................................................... 4-21
Section VIII. Fuze Setting ....................................................................................................................... 4-23
Section IX. Resetting Fuzes ................................................................................................................. 4-28
Section X. Fuze Wrench/Setting.......................................................................................................... 4-29
Section XI. Propelling Charges............................................................................................................. 4-30
XII. Adjustment of Propelling Charge ....................................................................................... 4-31
CHAPTER XIII. Unused Propelling Charge Increments .............................................................................. 4-34

APPENDIX 5 FOREIGN AMMUNITION (NATO) ..................................................................................... 5-1

APPENDIX A REFERENCES................................................................................................................... A-0

APPENDIX B COMPONENTS OF END ITEM AND BASIC ISSUE ITEMS ............................................ B-1

APPENDIX C ADDITIONAL AUTHORIZATION LIST ITEMS.................................................................. C-0

D EXPENDABLE/DURABLE SUPPLIES AND MATERIALS LIST...................................... D-0

ALPHABETICAL INDEX.................................................................................................... Index 0

Change 5 iii

M29A1 81-mm Mortar
1-0

CHAPTER 1
INTRODUCTION

Section I. GENERAL INFORMATION

SCOPE.

Type of Manual. Operator’s
Model Number and Equipment Name. M29A1 81-mm Mortar
Purpose of Equipment. High angle fire for close-in support of ground troops.

MAINTENANCE FORMS AND RECORDS.

Department of the Army forms and procedures used for equipment maintenance will be those prescribed by DA PAM 738-
750, The Army Maintenance Management System (TAMMS).

1-1

HAND RECEIPT (-HR) MANUALS.

This manual has a companion document with a TM number followed by “-HR” (which stands for Hand Receipt). The TM
9-1015-200-10-HR consists of preprinted hand receipts (DA Form 2062) that list end item related equipment (i.e., COEI,
BII, and AAL) you must account for. As an aid to property accountability, additional -HR manuals may be requisitioned
from the following source in accordance with procedures in Chapter 3, AR 310-2:

Commander
US Army Adjutant General Publication Center
2800 Eastern Boulevard
Baltimore, MD 212202896

NOMENCLATURE CROSS-REFERENCE LIST.

This listing includes nomenclature cross-references used in this manual.

Common Name Official Nomenclature
Clevis locking pin Quick release pin

REPORTING EQUIPMENT IMPROVEMENT RECOMMENDATIONS (EIR’s).

If your 81-mm mortar needs improvement, let us know. Send us an EIR. You, the user, are the only one who can tell us
what you don’t like about your equipment. Let us know why you done like the design or performance. Put it on an SF 368
(Quality Deficiency Report). Mall It to us at Commander, US Army Armament, Research & Development Engineering
Center, ATTN: AMSTA-AR-QAW-A (R), Rock Island, IL 61299-7300. We’ll send you a reply.

Change 5 1-2

Section II. EQUIPMENT DESCRIPTION

EQUIPMENT CHARACTERISTICS, CAPABLITIES, AND FEATURES.

Equipment Characteristics. Provide high angle fire for close-range support of ground troops.

Capabilities and Feature
Muzzle-loading
High angle fire
Portable
Smooth bore

Major Weapon System Components:
(a) Canon Assembly M29A1
(b) Bipod Assembly M23A1
(c) Baseplate M3
(d) Sightunit M53 or M3A1

1-3

LOCATION AND DESCRIPTION OF MAJOR COMPONENTS.

Cannon Assembly M29A1. Has a base cap and fixed firing pin for drop firing.
1-4

Bipod Assembly M23A1. Absorbs the shock of recoil in firing with a spring-type shock absorber.
1-5

LOCATION AND DESCRIPTION OF MAJOR COMPONENTS - Continued.

Baseplate M3. Supports and alines the mortar and is made of aluminum.
NOTE

Baseplate M23A1 is no longer stocked; therefore, only baseplate M3 is covered in this manual
even though there are still old baseplates out in the field.

1-6

Sightunit M53 Series. Is a standard sighting device used to lay the mortar in elevation and deflection.
1-7

LOCATION AND DESCRIPTION OF MAJOR COMPONENTS - Continued.
1-8

EQUIPMENT DATA.

Physical Characteristics.

Weight:
Cannon Assembly M29A1 ....................................................................... 28 Ibs (12.73 kg)
Bipod Assembly M23A1 .......................................................................... 40 lbs (18 kg)
Baseplate:
One piece M3................................................................................... 25.4 lbs (11.55 kg)
Two piece steel M23A1 ................................................................... 48 lbs (21.83 kg)
Sightunit
M53 .................................................................................................. 5.25 Ibs (2.39 kg)
M53A1 ............................................................................................. 5.25 lbs (2.39 kg)

Dimensions:
Overall length .......................................................................................... 51 in. (129.54 cm)
Width in carrying position ........................................................................ 14.3 in. (36.32 cm)
Maximum width ....................................................................................... 21 in. (53.34 cm)
Overall height on bipod ........................................................................... 37.5 in. (95.25 cm)
Diameter of baseplate ............................................................................. 21 in. (53.34 cm)

1-9

EQUIPMENT DATA - Continued.

Elevation:
Elevation (approx) . 800-1500 mils
Per turn of elevation crank (approx) ......................................................... 10 mils

Deflection
Right or left from center (approx) ............................................................ 95 mils

Total turns of handwheel for full traverse
(approx).................................................................................................... 19 turns

Total deflection by movement of bipod without
moving baseplate .................................................................................... 6400 mils

Rated of Fire.

Rounds per minute Period

Sustained ............................................3 (charge 8) ....................................... Indefinitely

5 (charge 6) ........................................ Indefinitely

Maximum ......................................12 (charge 8) ..................................... 2 minutes

12 (charge 6) ..................................... 5 minutes

1-10

Performance.

Range (approx) .................................. 4737
meters
14803.12 ft
4934.376 yd

Section III. TECHNICAL PRINCIPLES OF
OPERATION

1 Mortar is fired by dropping the cartridge down the
cannon, base end first.

2 Cartridge, falling under its own weight, causes primer
cap to strike the firing pin when bottom of cannon is
reached.

3 The propelling charge is ignited by exploding ignition
cartridge. Expanding gases force the cartridge from
the mortar.

4 Fins provide stability in flight for nose impact.

1-11

CHAPTER 2
OPERATING INSTRUCTIONS
Section I. DESCRIPTION AND USE OF OPERATOR’S CONTROLS AND INDICATORS

2-0

LOCKING SLEEVE
Locks sliding bracket in place.

SLIDING BRACKET
Use for coarse adjusting the cross-leveling of the mortar.

ADJUSTING NUT
Makes final fine adjustment in cross-leveling.

ELEVATING CRANK
Changes the elevation of the mortar.

TRAVERSING HANDWHEEL ASSEMBLY
Use for slow and fine adjustments in deflection.

TRAVERSING CRANK
Use to make rapid and coarse adjustments in deflection.

CLEVIS LOCKING PIN
Locks bipod to cannon; locks clevis to lug (projecting from the elevating mechanism housing) for traveling.

SIGHT SOCKET
Use to attach sightunit M53 or M53A1.

2-1

SIGHTUNIT M53 SERIES
2-2

2-3

INSTRUMENT LIGHT M53E1.
Illuminates sightunit M53 series for night operating.
Instrument light screws into the sightunit. Hand light is provided to illuminate scales and level vials.

2-4

AIMING POST M1A2.
Provides reference point for direct fire.

AIMING POST LIGHT M14
Illuminates aiming posts for night operation.
Mounted on aiming posts.

2-5

Section II. PREVENTIVE MAINTENANCE CHECKS AND SERVICES (PMCS)

The operator must perform scheduled services to be sure the 81-mm mortar will operate properly. Always keep in mind
the WARNINGS AND CAUTIONS before and during operation. If your equipment fails to operate, troubleshoot and use
the proper forms to report any deficiencies. See DA PAM 738-750.

Column B in the PMCS table is before operations checks. Column M is for monthly checks. When recording results of
PMCS, entries in the PMCS Item No. column will be used for the TM Item No. column on DA Form 2404.

The “Equipment Is NOT READY/AVAILABLE IF” column indicates deficiencies which must be corrected before you can
operate the 81-mm mortar.

Perform monthly as well as before operation PMCS if:

(1) You are the assigned operator and have not used the item since the last monthly inspection.

(2) You are operating the item for the first time.

2-6

OPERATOR/CREW PREVENTIVE MAINTENANCE CHECKS AND SERVICES

B - Before operation D - During operation A - After operation M - Monthly

ITEM INTERVAL ITEM TO BE INSPECTED Equipment is Not
NO BD AM PROCEDURE Ready/Available If:

1 DA FORM 24084
• a. Check to see if your weapon has been borescope: and pullover gaged within the past 90 days.

• Weapon has not bean borescope and pullover gaged within 90 days.
b. Update DA Form 2408-4 to reflect day’s firing.

After 5.000 rounds fired. weapon has not been borescope every 500 additional rounds.

2-7

OPERATOR/CREW PREVENTIVE MAINTENANCE CHECKS AND SERVICES - Continued

ITEM INTERVAL ITEM TO BE INSPECTED Equipment is Not
NO BD AM PROCEDURE Ready/Available If:

2 MORTAR
• Check that mortar is free of cracks, broken wed, rut or missing and damaged
Mortar has cracks, broken welds, or missing and damaged parts.
3
• CANNON ASSEMBLY
a. Check for foreign barrel and wipe dry. Can and lubricate exterior surface.

2-8

OPERATOR/CREW PREVENTIVE MAINTENANCE CHECKS AND SERVICES - Continued

ITEM INTERVAL ITEM TO BE INSPECTED Equipment is Not
NO BD AM PROCEDURE Ready/Available If:

•• b. Check for bulges, dents, and visible cracks. Check for evidence of gas leakage around
firing pin (1).

Barrel is bulged, dented, or visibly cracked or shows visual evidence of gas leakage around
firing pin.

c. Use RBC (item 7, app D) to thoroughly clean barrel bore after firing and for two consecutive
days thereafter.
NOTE
For nonfiring periods, barrel is cleaned and lubricated on a weekly basis.

2-9

OPERATOR/CREW PREVENTIVE MAINTENANCE CHECKS AND SERVICES - Continued

ITEM INTERVAL ITEM TO BE INSPECTED Equipment is Not
NO BD AM PROCEDURE Ready/Available If :

4 BASEPLATE
•
• a. Rotate U-shaped socket 360 degrees.
b. Check baseplate for cracks, broken welds, or loose, missing or damage parts.
5
• Socket does not rotate 360 degrees. Baseplate has cracks, broken welds, or missing or
damaged parts.

BIPOD ASSEMBLY

a. Check bipod assembly for cracks, broken welds, rust, or loose, missing or damaged parts.

Bipod assembly has racks, broken welds, or missing or damaged parts.

2-10

OPERATOR/CREW PREVENTIVE MAINTENANCE CHECKS AND SERVICES - Continued

ITEM INTERVAL ITEM TO BE INSPECTED Equipment is Not
NO BD AM PROCEDURE Ready/Available If :

•• b. Elevating (1) and traversing (2) mechanism assemblies must operate smoothly and without
binding through entire range of travel.

Elevating and/or traversing mechanism
assembles are inoperative.

• c. Clean and lubricate exposed
bearing surfaces.

• d. Test function the shock absorber
assembly (3) and barrel ring (4) by
operating manually with mortar in
high range .

Shock absorber assembly or barrel ring
is inoperative or binding.

2-11

OPERATOR/CREW PREVENTIVE MAINTENANCE CHECKS AND SERVICES - Continued

ITEM INTERVAL ITEM TO BE INSPECTED Equipment is Not
NO BD AM PROCEDURE Ready/Available If :

SIGHTUNIT M53 SERIES

• a. Check eyeshield (1) for damage. Check lenses and window for smears, scratches, cracks,
or other obstructions.

Image is totally obstructed.

• b. Level vials (2) must not be cracked,
broken or loose in mountings;
covers must not be missing.

Vials are cracked, broken or loose in mounting.

2-12

OPERATOR/CREW PREVENTIVE MAINTENANCE CHECKS AND SERVICES - Continued

ITEM INTERVAL ITEM TO BE INSPECTED Equipment is Not
NO BD AM PROCEDURE Ready/Available If :

SIGHTUNIT M53 SERIES

• c. Check rotation of the elevation knob (3) and deflection (azimuth) knob (4) over entire range
of movement. Motion must be smooth and even

Knobs have excessive backlash.

• d. Check index lines and scales (5).
They must be clear and distinct.

Scales and indexes cannot be read

2-13

OPERATOR/CREW PREVENTIVE MAINTENANCE CHECKS AND SERVICES - Continued

ITEM INTERVAL ITEM TO BE INSPECTED Equipment is Not
NO BD AM PROCEDURE Ready/Available If :

SIGHTUNIT M53 SERIES - Continued

• e. Check elevation (6) and deflection (azimuth) (7) worm mechanism backlash Must not
exceed 0.5 of a mil.

Azimuth scale slips when locked; backlash
exceed 0.5 of a mil.

• f. Check locking latch clamp (8) for
looseness and cracks. Also check that
locking latch secure sightunit to mortar.

Locking latch clamp broken and/or does not
secure sightunit.

2-14

OPERATOR/CREW PREVENTIVE MAINTENANCE CHECKS AND SERVICES - Continued

ITEM INTERVAL ITEM TO BE INSPECTED Equipment is Not
NO BD AM PROCEDURE Ready/Available If :

• g. Check the mounting surfaces are free of
nicks and burrs.

Nicks and burrs prevent proper seating in
holder.

• h. Check that deflection (azimuth) knob (4)
stays in position when locking knob (9) is
tightened.

Deflection (azimuth) knob (4) slips when
tightened.

2-15

OPERATOR/CREW PREVENTIVE MAINTENANCE CHECKS AND SERVICES - Continued

ITEM INTERVAL ITEM TO BE INSPECTED Equipment is Not
NO BD AM PROCEDURE Ready/Available If :

7 INSRTUMENT LIGHT M53E1 AND CASE M166

• a. Install batteries (1) and check switch,
lamps, and batteries for operation.

Lamps do not illuminate.

• b. Remove batteries (1) after operation
and check for corrosion
•
• c. Check leads for serviceability.
d. Check inside of case for cleanliness

2-16

OPERATOR/CREW PREVENTIVE MAINTENANCE CHECKS AND SERVICES - Continued

ITEM INTERVAL ITEM TO BE INSPECTED Equipment is Not
NO BD AM PROCEDURE Ready/Available If :

8 AIMING POST LIGHT M14 AND CHEST M14

• a. . Check case, receptacle, and brackets for crack

Case, receptable, or brackets are cracked.

2-17