**UH-1 SERIES**

**INSPECTION PLANNING GUIDE**

**INTERAGENCY COMMITTEE**

**for**

**AVIATION POLICY**

![](media/image1.wmf){width="1.575in" height="1.51875in"}

This UH-1 Inspection Planning Guide (IPG) supersedes

the UH-1 IPG dated March 26, 1996 and includes

Revision 1 (12 March 1997) and Revision 2 (March 1, 2002) \|

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

###  1 March 2002 \| 

**TABLE OF CONTENTS PAGE**

[Chapter/ Section]{.underline}

RECORD OF REVISIONS 3

CHAPTER 1 INTRODUCTION 6

WARNINGS, CAUTIONS, and NOTES DEFINED 7

FORMAT DEFINED 8

####  POINTS OF CONTACT 8 \|

####  LIST OF DEFINITIONS 10 \| 

CHAPTER 2 INSPECTION DESCRIPTIONS 15

INSPECTION SCHEDULE CHART 16

SPECIAL INSPECTIONS LISTING 17

CONDITIONAL INSPECTIONS (AIRFRAME) LISTING 18

CONDITIONAL INSPECTIONS (ENGINE) LISTING 19

INSPECTIONS

CHAPTER 3 PREVENTIVE MAINTENANCE INSPECTION (P.M.I.) 20

CHAPTER 4 DETAIL #1 25

CHAPTER 5 DETAIL #2 28

CHAPTER 6 DETAIL #3 30

CHAPTER 7 SPECIAL INSPECTIONS 34

CHAPTER 8 CONDITIONAL INSPECTIONS (AIRFRAME) 38

CHAPTER 9 CONDITIONAL INSPECTIONS (ENGINE) 54

APPENDIX Letter from Bell Textron

Ref: Overhaul and Retirement Schedule,

Manuals and Technical Assistance 66 \|

**RECORD OF REVISIONS**

Originally accepted by the FAA on 26 March 1996.

Revision 1 (12 March 1997):

+----------+-------------+----------------+-------------------------+---+
| **P      |             |                |                         |   |
| OSTED:** |             |                |                         |   |
+----------+-------------+----------------+-------------------------+---+
|          |             | **REVISION     | **PAGE NUMBER(S)**      |   |
|          |             | NUMBER**       |                         |   |
+----------+-------------+----------------+-------------------------+---+
| **DATE** | **BY**      |                |                         |   |
+----------+-------------+----------------+-------------------------+---+
|          |             | Rev. 1         | > Removed page 18,      |   |
|          |             |                | >                       |   |
|          |             | (12 March      | > Inserted new page 18. |   |
|          |             | 1997)          |                         |   |
+----------+-------------+----------------+-------------------------+---+
|          |             | Rev. 1         | > Removed pages 23 to   |   |
|          |             |                | > 26,                   |   |
|          |             | (12 March      | >                       |   |
|          |             | 1997)          | > Inserted new pages    |   |
|          |             |                | > 23-26.                |   |
+----------+-------------+----------------+-------------------------+---+
|          |             | Rev. 1         | > Removed page 29,      |   |
|          |             |                | >                       |   |
|          |             | (12 March      | > Inserted new page 29. |   |
|          |             | 1997)          |                         |   |
+----------+-------------+----------------+-------------------------+---+
|          |             | #####  Rev. 2  | Cover page date "March  |   |
|          |             |                | 12, 1997"               |   |
|          |             | (1 Mar 2002)   |                         |   |
|          |             |                | Changed to "This UH-1   |   |
|          |             |                | Inspection Planning     |   |
|          |             |                | Guide (IPG) supersedes  |   |
|          |             |                | the UH-1 IPG dated      |   |
|          |             |                | March 26, 1996, and     |   |
|          |             |                | includes Revision 1 (12 |   |
|          |             |                | March 1997) and         |   |
|          |             |                | Revision 2 1 March 1,   |   |
|          |             |                | 2002) and "1 March      |   |
|          |             |                | 2002"                   |   |
+----------+-------------+----------------+-------------------------+---+
|          |             | #####  Rev. 2  | Page 2 Changed to       |   |
|          |             |                | include "Points of      |   |
|          |             | (1 Mar 2002)   | Contact", "Definitions" |   |
|          |             |                | and "Appendix"          |   |
+----------+-------------+----------------+-------------------------+---+
|          |             | Rev. 2         | Page 3 Changed to       |   |
|          |             |                | indicated "Revision 2,  |   |
|          |             | (1 Mar 2002)   | 1 March 2002" updates.  |   |
+----------+-------------+----------------+-------------------------+---+
|          |             | #####  Rev. 2  | Page 6, General,        |   |
|          |             |                | "WARNING" changed to    |   |
|          |             | (1 Mar 2002)   | include "UH-1           |   |
|          |             |                | [D]{.underline} and H"  |   |
|          |             |                | helicopters.            |   |
+----------+-------------+----------------+-------------------------+---+

+----------+-------------+----------------+-------------------------+---+
|          |             | #####  Rev. 2  | # Page 6, thir          |   |
|          |             |                | d sentence from end of  |   |
|          |             | (1 Mar 2002)   | page now states, "An ow |   |
|          |             |                | ner/operator shall deve |   |
|          |             |                | lop a checklist for eac |   |
|          |             |                | h inspection outlined i |   |
|          |             |                | n this document. [Refer |   |
|          |             |                |  to (current version) T |   |
|          |             |                | M 55-1520-210-PMD UH-1H |   |
|          |             |                | /V, and EH-1H/X Aircraf |   |
|          |             |                | t Preventive Maintenanc |   |
|          |             |                | e Daily Inspection Chec |   |
|          |             |                | klist when developing c |   |
|          |             |                | hecklist."]{.underline} |   |
+----------+-------------+----------------+-------------------------+---+
|          |             | #####  Rev. 2  | Page 4 Added to 1-1.    |   |
|          |             |                | General in the first    |   |
|          |             | (1 Mar 2002)   | paragraph, "This        |   |
|          |             |                | includes a review of    |   |
|          |             |                | the aircraft, aircraft  |   |
|          |             |                | engines, appliances,    |   |
|          |             |                | and the forms and       |   |
|          |             |                | records for any         |   |
|          |             |                | recorded discrepancies  |   |
|          |             |                | and for any applicable  |   |
|          |             |                | Airworthiness           |   |
|          |             |                | Directives, Safety of   |   |
|          |             |                | Flight Messages, ASAMS, |   |
|          |             |                | TM's TB's, etc. that    |   |
|          |             |                | must be complied with." |   |
+----------+-------------+----------------+-------------------------+---+
|          |             | #####  Rev. 2  | # Page 6, "PO           |   |
|          |             |                | INTS OF CONTACT" added. |   |
|          |             | (1 Mar 2002)   |                         |   |
+----------+-------------+----------------+-------------------------+---+
|          |             | #####  Rev. 2  | # New Page 10 Now       |   |
|          |             |                | includes "Definitions". |   |
|          |             | (1 Mar 2002)   |                         |   |
+----------+-------------+----------------+-------------------------+---+
|          |             | #####  Rev. 2  | Page 8 Now page 16.     |   |
|          |             |                | Chapter 2, Inspection   |   |
|          |             | (1 Mar 2002)   | Descriptions, 2-7,      |   |
|          |             |                | "NOTE", 3., changed to  |   |
|          |             |                | include, "THE "ANNUAL   |   |
|          |             |                | CYCLE" STARTS AGAIN     |   |
|          |             |                | WHEN ALL INSPECTIONS    |   |
|          |             |                | ARE COMPLETED."         |   |
+----------+-------------+----------------+-------------------------+---+
|          |             | #####  Rev. 2  | # Page 12 Now pag       |   |
|          |             |                | e 20. Chapter 3, Preven |   |
|          |             | (1 Mar 2002)   | tive Maintenance Inspec |   |
|          |             |                | tion (P.M. I.), Section |   |
|          |             |                |  I, 2., now states, 2., |   |
|          |             |                |  "Review service instru |   |
|          |             |                | ctions for maintenance  |   |
|          |             |                | and inspection requirem |   |
|          |             |                | ents for installed kits |   |
|          |             |                | , [MWOs and STCs as app |   |
|          |             |                | ropriate."]{.underline} |   |
+----------+-------------+----------------+-------------------------+---+

+----------+-------------+----------------+-------------------------+---+
|          |             | #####  Rev. 2  | # Page 12 Now           |   |
|          |             |                | page 20. Chapter 3, Pre |   |
|          |             | (1 Mar 2002    | ventive Maintenance Ins |   |
|          |             |                | pection (P.M. I.), Sect |   |
|          |             |                | ion I, 5., now states,  |   |
|          |             |                | 5., "Ensure all applica |   |
|          |             |                | ble Airworthiness Direc |   |
|          |             |                | tives (Safety of Flight |   |
+----------+-------------+----------------+-------------------------+---+
|          |             | #####  Rev. 2  | # Page 13               |   |
|          |             |                |  Now page 21. Chapter 3 |   |
|          |             | (1 Mar 2002    | , Preventive Maintenanc |   |
|          |             |                | e Inspection (P.M. I.), |   |
|          |             |                |  Section III, 19., now  |   |
|          |             |                | states, "Check main rot |   |
|          |             |                | or for proper lubricant |   |
|          |             |                |  level, inspect for evi |   |
|          |             |                | dence of leakage, and o |   |
|          |             |                | bvious contamination. [ |   |
|          |             |                | Not applicable if aircr |   |
|          |             |                | aft is modified with gr |   |
|          |             |                | ease hub]{.underline}." |   |
+----------+-------------+----------------+-------------------------+---+

1\. All personnel to whom this IPG is furnished shall keep it up to date
with the changes and additions furnished to them.

2\. Each IPG shall have the date of the last revision on each page.

**CHAPTER 1**

**INTRODUCTION**

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**1-1. GENERAL**

This document, the UH-1 Series Inspection Planning Guide (IPG) is
available to operators of UH-1 series helicopters (except UH-1N models)
for the purpose of providing operators with a choice in maintenance
programs. In accordance with the inspection standards set forth in the
specific aircraft type certificate, the owner/operator must use the
complete inspection program developed by the applicable military
service. This includes a review of the aircraft, aircraft engines, \|

appliances, and the forms and records for any recorded discrepancies and
for any \|

applicable Airworthiness Directives, Safety of Flight Messages, ASAMS,
TM's TB's, \|

etc. that must be complied with. \|

This document, the IPG, has been developed as an alternative reasonable
basis for inspection program development.

The owner/operator conducting public use operations may use this
document as a reasonable basis for the development of an inspection
program to assure an equivalent level of safety.

***WARNING***

***UNLESS SPECIFICALLY DESIGNATED HEREIN, STANDARDS FOR SERVICEABILITY
FOR THE AIRFRAME MAINTENANCE AND INSPECTION CONTAINED IN THIS DOCUMENT
ARE FOUND IN THE APPLICABLE MILITARY MAINTENANCE DOCUMENT FOR THESE
SPECIFIC MAKE AND MODELS OF AIRCRAFT, I.E. NAVY UH-1E, UH-1L, TH-1L,
HH-1K; ARMY UH-1B, UH-1C/M, UH-1D/H; AIR FORCE HH-1H). \|***

***UNLESS SPECIFICALLY DESIGNATED HEREIN STANDARDS FOR SERVICEABILITY
FOR THE ENGINE MAINTENANCE AND INSPECTION CONTAINED IN THIS DOCUMENT ARE
FOUND IN THE APPLICABLE MILITARY MAINTENANCE DOCUMENT OR THE APPLICABLE
ALLIED SIGNAL LYCOMING DOCUMENT FOR THESE SPECIFIC MODELS OF ENGINE.(
T53L11, T53L13, T53L703)***

This document contains the requirements for the Preventive Maintenance
Inspection

(P.M.I.), Detail (#1-#2-#3) Inspections, Special Inspections and
Conditional

Inspections that shall be performed on the UH-1 series helicopters.

Inspections required herein shall be performed by a properly rated
repairman (under

14 Code of Federal Regulations, Part 65) or a Federal Aviation
Administration

certified Airframe and Powerplant mechanic.

An owner/operator shall develop a checklist for each inspection outlined
in this

document. Refer to (current version) TM 55-1520-210-PMD UH-1H/V, and
EH-1H/X Aircraft \|

Preventive Maintenance Daily Inspection Checklist when developing
checklist. \|

Maintenance functions and definitions of terms shall be in accordance
with applicable military maintenance manual for the UH-1 Series unless
otherwise stipulated in this document.

The IPG is applicable to a standard UH-1 series helicopter operating in
a flight profile similar to the US military.

**NOTE**

UH-1 HELICOPTERS USED FOR **REPETITIVE** HEAVY LIFT AND OTHER UNIQUE
OPERATIONS (LOGGING, WATER BUCKET, LONG LINE, ETC.), SHALL REQUIRE
ADDITIONAL AND/OR MORE FREQUENT INSPECTIONS AS DEEMED NECESSARY BASED ON
OPERATIONAL EXPERIENCE AND/OR ALERT SERVICE BULLETINS AND/OR
AIRWORTHINESS DIRECTIVES. UH-1 HELICOPTERS MODIFIED THROUGH
INCORPORATION OF SUPPLEMENTAL TYPE CERTIFICATES OR EQUIPPED WITH SPECIAL
MISSION KITS SHALL REQUIRE ADDITIONAL INSPECTIONS AS DEEMED NECESSARY.

The IPG is primarily presented for UH-1H model helicopters. Inspection
requirements peculiar to 540 main rotor equipped helicopters are denoted
"540 M/R". The IPG is also primarily presented for the T53L11, T53L13
and T53L703 engines. The engine should be maintained and inspected in
accordance with the manufacturer's maintenance manual and the
appropriate manufacturer's service bulletins.

**NOTE**

AN ENGINE HEALTH INDICATOR TEST IS NORMALLY A PRE-FLIGHT FUNCTION
PERFORMED BY THE PILOT AND HAS NOT BEEN INCLUDED IN THE IPG. HOWEVER,
THE OPERATOR SHOULD ESTABLISH A METHOD FOR ENGINE TREND MONITORING TO
EVALUATE ENGINE HEALTH AND PERFORMANCE. A SUGGESTED METHOD FOR ENGINE
TREND MONITORING IS THE HEALTH INDICATOR TEST (HIT) AS DESCRIBED IN
APPROPRIATE US ARMY MANUALS.

**1-2. WARNING, CAUTIONS, AND NOTES DEFINED.**

***WARNING***

***AN INSPECTION PROCEDURE, PRACTICE, ETC., WHICH IF NOT CORRECTLY
FOLLOWED, COULD RESULT IN PERSONAL INJURY OR LOSS OF LIFE.***

**CAUTION**

**AN INSPECTION PROCEDURE, PRACTICE, ETC., WHICH, IF NOT STRICTLY**

**OBSERVED, COULD RESULT IN DAMAGE TO OR DESTRUCTION OF EQUIPMENT.**

**NOTE**

AN INSPECTION PROCEDURE, CONDITION, ETC., WHICH IS ESSENTIAL TO
HIGHLIGHT

**1-3. FORMAT DEFINED**

The IPG is divided into:

[Example:]{.underline}

Chapters, **CHAPTER 7 SPECIAL INSPECTIONS**

Sections, **SECTION V. LOWER PYLON**

Headings, **8-1. HARD LANDING**

Paragraphs, **10.** Tail rotor gearbox.

and subparagraphs. **10.1.** Remove tail rotor

gearbox. Check for cracks. Etc.

**a.** Main rotor blades.

**(1)** Bolt contact etc.

**(a)** Remove spline etc.

**1.** Tighten bolt etc.

**1-4. POINTS OF CONTACT \|**

[www.gsa.gov/aircraftpolicy](http://www.gsa.gov/aircraftpolicy) Web Site
for the General Services Administration\| Aircraft Management Policy
Division. The \|

"caretaker" of the Inspection Planning Guides. \|

Charlie Elkins \|

\(256\) 955-0773 ATCOM UH-1 contact. \|

Susan Lewis \|

\(256\) 955-0773 ATCOM OH-58 contact. \|

Paul Elliott \|

\(602\) 231-3077 \|

<paul.Elliott@honeywell.com> \|

Russ Smith \|

\(602\) 231-3599 \|

<russ.smith@honeywell.com> \|

Dan Grady \|

\(602\) 231-3348

<dan.grady@honeywell.com> Honeywell contacts for T53 engines. Technical
\|

publications. \|

National Technical Information Service \|

1 800 553-6847 \|

\(703\) 605-6000 \|

5285 Port Royal Road \|

Springfield, VA 22161 Maintenance manuals for Army helicopters. \|

Randy Stewart \|

Department of Energy \|

Senior Aviation Policy Officer, MA-10 \|

Office of Aviation Management \|

1000 Independence Ave., SW, \|

Rm 9H-063 \|

Washington, DC 20585 \|

\(202\) 586-6171 IPG Work Group \|

Andrew L. Kelley \|

Product Support Engineer \|

Bell Helicopter Textron \|

PO Box 482 \|

Fort Worth, TX 76101 \|

\(817\) 280-4074 IPG Work Group \|

Richard Thomas \|

Federal Aviation Administration \|

FTW-Aircraft Evaluation Group (AEG) \|

Fort Worth, Texas 76193-0270 \|

\(817\) 222-5272 IPG Work Group \|

Mike Miles \|

General Services Administration \|

1800 F Street, NW Rm 1221A \|

Washington, DC 20405 \|

\(202\) 219-1356 IPG Work Group \|

**Definitions \|**

**\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_**

**[AIRCRAFT]{.underline}** means a device that is used or intended to be
used for flight.

**[AIRCRAFT ENGINE]{.underline}** means an engine that is used or
intended to be used for propelling aircraft. It includes
turbo-superchargers, appurtenances, and accessories necessary for its
functioning, but does not include propellers.

**[AIRFRAME]{.underline}** means the fuselage, booms, nacelles,
cowlings, fairings, airfoil surfaces (including rotors but excluding
propellers and rotating airfoils of engines), and landing gear of an
aircraft and their accessories and controls.

**[AIRCRAFT MAINTENANCE]{.underline}** means that work which is required
to be performed by an appropriately certificated and qualified
person(s).

**[AIRWORTHINESS DIRECTIVE]{.underline}** means a maintenance procedure
dictated by the Federal Aviation Administration that must be performed
on an aircraft in order to remain airworthy.

**[APPROVED]{.underline}** unless used with reference to another person,
means approved by the FAA Administrator.

**[APPLIANCE]{.underline}** means any instrument, mechanism, equipment,
part, apparatus, appurtenance, or accessory, including communications
equipment, that is used or intended to be used in operating or
controlling an aircraft in flight, is installed in or attached to the
aircraft, and is not part of an airframe, engine, or propeller.

**[CALIBRATION]{.underline}** means making precise measurements and
adjustments to equipment or systems in order to obtain optimum
performance and to certify that output data falls within prescribed
tolerances.

**[CAUTION]{.underline}** means a maintenance or inspection procedure,
practice, etc., which, if not strictly observed, could result in damage
to or destruction of equipment.

**[CHECK]{.underline}** means an action taken to examine and verify, in
accordance with established procedures and requirements, the condition
or status of an aircraft, its systems, components, and/or accessories.

**[CIVIL AIRCRAFT]{.underline}** means an aircraft that may or may not
be owned or leased by the United States Government or a State or local
government; that holds, or is cabable of holding an airworthiness
certificate; and is cabable of transporting passengers or engaging in
commercial purposes. (see PUBLIC AIRCRAFT)

**[COMPONENT]{.underline}** any self-contained part, combination of
parts, subassemblies or units, which perform a distinctive function
necessary to the operation of the airframe, powerplant or propeller.

**[CONDITIONAL INSPECTION]{.underline}** means an inspection which is
contingent upon specific conditions or incidents that arise, and only
because of these conditions or incidents. Examples of these conditions
or incidents are hard landings, overspeed, and sudden stoppage. An
inspection is required in such cases before further flight.

**(ENGINE)** **CYCLE** means an engine start and shutdown procedure to
be counted as "1". For the purposes of this document and historical
purposes (2 cycles per flight hour plus 25%) is the method recommended
to determine the number of cycles on engines that have not been logging
cycles. After that, 1 cycle per flight hour.

**[DMWR]{.underline}** (pronounced dimwar) means Depot Maintenance Work
Requirement. It is a document that details maintenance and inspection
criteria for specific components.

**[FOREIGN OBJECT DAMAGE]{.underline}** (FOD) means damage to an
aircraft, airframe. or engine caused by a foreign object that is not
part of the aircraft, or has broken loose of the aircraft and caused
damage.

**[GROUND RUN (see RUN-UP)]{.underline}** means operating the aircraft
on the ground, with no intention of taking off, from a normal start thru
flight idle, as a minimum.

[**HARD LANDING**]{.underline} means any accident or incident in which
ground impact of the helicopter causes severe pitching of main rotor,
allowing hard contact of hub with mast, or results in yielding or
noticeable cracking of fuselage pylon support structure or landing gear.

**[HARD-TIME]{.underline}** means a primary maintenance process that
requires an appliance or part be periodically overhaul in accordance
with the Agency's maintenance manual or that it be removed from service.

**[HEALTH INDICATOR]{.underline}** **[(ENGINE) TEST]{.underline}** (HIT)
means a method for engine trend monitoring to evaluate engine health and
performance.

**[INSPECT]{.underline}** means a method of qualifying the condition or
status of the aircraft, its systems, components, and/or accessories to
specific standards and requirements.

**[INTERMEDIATE INSPECTION]{.underline}** means an inspection that is
performed each 25 hours.

**[MAINTENANCE INSPECTIONS]{.underline}** include daily/preflight,
segment, safety, service, special, and numbered inspections. These
inspections vary in scope and frequency of performance according to
types of aircraft.

**[MODIFICATION WORK ORDER]{.underline}** (MWO) means an authorization
to perform a modification on an aircraft to correct or enhance an
existing condition. This is a military term and is similar to a
commercial model service instruction.

**[MAJOR ALTERATIONS]{.underline}** means an alteration not listed in
the aircraft, or aircraft engine/rotor specifications that (1) might
appreciably affect weight, balance, structural strength, performance,
powerplant operation, flight characteristics, or other qualities
affecting airworthiness; or (2) is not done according to accepted
practices, or cannot be done by elementary operations (refer to

Part 43).

**[MAJOR REPAIR]{.underline}** means a repair that (1) if improperly
done, might appreciably affect weight, balance, structural strength,
performance, powerplant operations, flight characteristics, or other
qualities of airworthiness; or (2) is not done according to accepted
practices, or cannot be done by elementary operations (refer to Part
43).

**[MAST BUMPING]{.underline}** or flapping-stop contact means the
condition which occurs when the main yoke contacts the mast and may
result in a fractured mast and rotor seperation. It usually occurs
during; slope landings, rotor startup/coastdown, or when the flight
envelope is exceeded.

**[MINIMUM EQUIPMENT LIST]{.underline}** (MEL) means a regulatory
authorization to continue to operate an aircraft with inoperable
instruments or equipment. The aircraft may be operated under all
applicable conditions and limitations contained in the minimum equipment
list.

**[MINOR]{.underline}** **[ALTERATION]{.underline}** means a
modification that is an alteration other than a major alteration.

**[MINOR REPAIR]{.underline}** means a repair that is other than a major
repair.

**[NOTE]{.underline}** means an inspection or maintenance procedure,
condition, et**c.**, which is essential to highlight

**[ON CONDITION ITEM]{.underline}** (OC) means an item of equipment that
must be restricted to one on which a determination of continued
airworthiness may be made by a visual check, measurement, test, or other
means.

**[OPERATIONAL CHECK]{.underline}** means an \"in motion\" or \"power
on\" test for determining that an item of equipment will operate at a
specified performance level.

**[OVERHAUL]{.underline}** means the complete disassembly, cleaning,
inspection, necessary replacement or repair of parts, reassembly,
adjustment, and testing of an item or equipment in accordance with
recommended procedures.

**[PREVENTIVE MAINTENANCE]{.underline}** means simple or minor
preservation operations and the replacement of small standard parts not
involving complex assembly operations. It is corrective action taken
before it becomes necessary to make a major repair.

**[PREVENTIVE MAINTENANCE INSPECTION]{.underline}** (P.M.I.) means an
inspection which is accomplished each 12 1/2 flight hours or every 14
calendar days, whichever occurs first.

**[PUBLIC AIRCRAFT]{.underline}** means an aircraft used only for the
United States Government, an aircraft owned by the Government and
operated by any person for purposes related to crew training, equipment
development, or demonstration, an aircraft owned and operated by the
government of a State, the District of Columbia, or a territory or
possession of the United States or a political subdivision of one of
these governments, an aircraft exclusively leased for at least 90
continuous days by the government of a State, the District of Columbia,
or a territory or possession of the United States or a political
subdivision of one of these governments, an aircraft owned or operated
by the armed forces or chartered to provide transportation to the armed
forces. In this definition, the following definitions apply:

\(1\) COMMERCIAL PURPOSES means the transportation of persons or
property for compensation or hire, but does not include the operation of
an aircraft by the armed forces for reimbursement when that
reimbursement is required by any Federal statute, regulation, or
directive, in effect on November 1, 1999, or by one government on behalf
of another government under a cost reimbursement agreement if the
government on whose behalf the operation is conducted certifies to the
Administrator of the Federal Aviation Administration that the operation
is necessary to respond to a

significant and imminent threat to life or property (including natural
resources) and that no service by a private operator is reasonably
available to meet the threat.

\(2\) GOVERNMENTAL FUNCTION means an activity undertaken by a
government, such as national defense, intelligence missions,
firefighting, search and rescue, law enforcement (including transport of
prisoners, detainees, and illegal aliens), aeronautical research, or
biological or geological resource management.

\(3\) QUALIFIED NON-CREWMEMBER means an individual, other than a member
of the crew, aboard an aircraft\--

\(A\) operated by the armed forces or an intelligence agency of the
United States Government; or

\(B\) whose presence is required to perform, or is associated with the
performance of, a governmental function.

\(4\) ARMED FORCES has the meaning given such term by section 101 of
title 10.

An aircraft does not qualify as a public aircraft when the aircraft is
used for commercial purposes or to carry an individual other than a
crewmember or a qualified non-crewmember.

AIRCRAFT OWNED OR OPERATED BY THE ARMED FORCES qualifies as a public
aircraft if:

\(A\) the aircraft is operated in accordance with title 10;

\(B\) the aircraft is operated in the performance of a governmental
function under title 14, 31, 32, or 50 and the aircraft is not used for
commercial purposes; or

\(C\) the aircraft is chartered to provide transportation to the armed
forces and the Secretary of Defense (or the Secretary of the department
in which the Coast Guard is operating) designates the operation of the
aircraft as being required in the national interest.

LIMITATION An aircraft that is owned or operated by the National Guard
of a State, the District of Columbia, or any territory or possession of
the United States, qualifies as a public aircraft only to the extent
that it is operated under the direct control of the Department of
Defense.

**[REPAIR]{.underline}** means the restoration of an item of equipment
to a serviceable condition after fault detection.

**[RUN UP (see GROUND RUN)]{.underline}** means operation of the
aircraft from normal start thru flight idle. Flight of the aircraft may
be planned.

**[SPECIAL INSPECTION]{.underline}** means an inspection, in addition to
the P.M.I., Intermediate and Periodic Inspections, that are inspections
performed on a calendar basis, a cycle basis, a combination of
hourly/calendar basis, or following the installation of a major
component such as a gearbox installation.

**[TIME CONTROLLED COMPONENT]{.underline}** means a part or component
which has an established service life, at which time certain maintenance
must be performed or the item disposed of as unserviceable. The service
life may be based on operating hours, cycles, landings, calendar time,
or combinations of these.

**[UNSALVAGEABLE]{.underline}** means an aircraft part that should not
be returned to aviation use as defined by Federal Aviation
Administration (FAA) Advisory Circular

(AC) No. 21-38 "Disposition of Unsalvageable Aircraft Parts and
Materials

(7-5-94).". Persons disposing of unsalvageable aircraft parts and
materials should, when appropriate, mutilate those parts and materials
prior to release. Mutilation should be accomplished in such a manner
that the parts become unusable for their original intended use (see AC
No. 21-38).

**[VISUAL]{.underline}** **[INSPECTION]{.underline}** means an
inspection of an item of equipment for cleanliness, and deterioration of
parts or materials by visual means.

**[WARNING]{.underline}** means a maintenance or inspection procedure,
practice, etc., which if not correctly followed, could result in
personal injury or loss of life.

**[WIRE STRIKE]{.underline}** Protection System (WSPS) means a basic
system consisting of an upper cutter assembly, a windshield
deflector/cutter assembly, and a lower cutter assembly that provides
protection against frontal impacts with horizontally strung mechanical
and power transmission wires.

**[SAFETY OF FLIGHT MESSAGE]{.underline}** means an Army issued message
that details a method to inspect, maintain, repair, or replace a
component of a U.S. Army aircraft, usually an OH-58 or UH-1 helicopter.
SOF could also apply to flight procedures, operating limits, or
operational policy.

**CHAPTER 2**

**INSPECTION DESCRIPTIONS**

**\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_**

**NOTE**

PRIOR TO PLACING AN AIRCRAFT ON THIS PROGRAM, A P.M.I., DETAIL'S #1, #2,
AND #3, AND ANY OTHER SPECIAL INSPECTIONS THAT MAY BE REQUIRED, OR AN
INSPECTION FOR INITIAL CERTIFICATION, SHOULD BE ACCOMPLISHED.

**2-1. P.M.I.**

P.M.I. is found in Chapter 3 and is accomplished each 10 flight hours or
every

14 calendar days, whichever occurs first.

**2-2. Detail #1**

Is found in Chapter 4 and is accomplished each 50 flight hours.

**2-3. Detail #2**

Is found in Chapter 5 and is accomplished each 100 flight hours.

**2-4. Detail #3**

Is found in Chapter 6 and is accomplished each 150 flight hours.

**2-5. SPECIAL INSPECTIONS**

In addition to the P.M.I. and the Detail #1, #2, and #3 Inspections,
required

Special Inspections found in Chapter 7 of the IPG are performed on a
calendar basis, a combination of hourly/calendar basis, or following the
installation of a major

component such as a gearbox installation.

**2-6. CONDITIONAL INSPECTIONS (AIRFRAME)**

Conditional Inspections (Airframe) found in Chapter 8 of the IPG are

inspections required as a result of unusual events such as hard landings
or

sudden stoppage of rotor.

**2-7. CONDITIONAL INSPECTIONS (ENGINE)**

Conditional Inspections (Engine) found in Chapter 9 of the IPG are
inspections required as a result of an unusual event such as engine oil
filter bypass or engine overtemperature.

**NOTE**

THERE ARE NO PRESCRIBED INTERVALS FOR CONDITIONAL INSPECTIONS.

**INSPECTION SCHEDULE CHART**

**[INSPECTION SCHEDULES]{.underline}**

***[Flight Hours]{.underline}***

**[/ 50 100 150 200 250 300]{.underline}**

***[Inspection]{.underline}***

***P.M.I. Every 10 Flight Hours or 14 Days, whichever occurs first.***

***DETAIL #1 X X X X X X***

***DETAIL #2 X X X***

***DETAIL #3 X X***

**NOTE**

1\. IF AN AIRCRAFT WILL BE OUT OF SERVICE MORE THAN 30 DAYS, A P.M.I.
SHALL BE PERFORMED PRIOR TO RETURNING THE AIRCRAFT TO SERVICE.

> 2\. IF AN AIRCRAFT IS OUT OF SERVICE MORE THAN 14 DAYS, A RUN-UP IN
> ACCORDANCE WITH APPROPRIATE MANUALS IS STRONGLY RECOMMENDED.

3\. THE COMPLETE AIRCRAFT MUST BE INSPECTED WITHIN 12 CALENDAR MONTHS,
WHICH MEANS ALL THREE DETAILS MUST HAVE BEEN PERFORMED. IF AN AIRCRAFT
FLIES LESS THAN 150 HOURS IN 12 CALENDAR MONTHS, THE REMAINDER OF THE
DETAIL INSPECTIONS MUST BE PERFORMED. IF AN AIRCRAFT FLIES GREATER THAN
150 HOURS, THE INSPECTION CYCLE IS CONTINUED. THE "ANNUAL \|

CYCLE" STARTS AGAIN WHEN ALL INSPECTIONS ARE COMPLETED. SEE INSPECTION
SCHEDULE CHART \| ABOVE.

4\. ENGINE INSPECTIONS AND RETIREMENT LIFE LIMITED INTERVALS - REFER TO
MILITARY MAINTENANCE DOCUMENT OR THE ALLIED SIGNAL LYCOMING MAINTENANCE
DOCUMENT.

5\. COMPONENT OVERHAUL AND RETIREMENT LIFE LIMITED INTERVALS - REFER TO
APPLICABLE MILITARY MAINTENANCE DOCUMENT OR MANUFACTURERS MAINTENANCE
DOCUMENT.

**2-8. SPECIAL INSPECTIONS LISTING (CHAPTER 7)**

In addition to the P.M.I. and the Detail #1, #2, and #3 Inspections,
Special Inspections are performed on a calendar basis, a combination of
hourly/calendar basis, or following the installation of a major
component such as a gearbox installation.

PAGE

**1. 7-1. AFTER EACH INSTALLATION. 34**

**2. 7-2. AFTER FIRST FLIGHT, AFTER EACH INSTALLATION. 34**

**3. 7-3. BETWEEN 5 AND 10 HOURS, AFTER EACH INSTALLATION. 34**

**4. 7-4. EACH 25 HOURS OF OPERATION. 34**

**5. 7-5. EACH 100 HOURS OR 120 DAYS, WHICHEVER OCCURS FIRST. 35**

**6. 7-6. 100 HOURS AFTER EACH INSTALLATION. 35**

**7. 7-7. EACH 300 HOURS OR 6 MONTHS OF BATTERY OPERATION. 35**

**8. 7-8. EACH 12 MONTHS MAGNETIC (MAG) COMPASS AND**

**RADIO MAGNETIC INDICATOR (RMI) CALIBRATION. 35**

**9. 7-9. EACH 600 HOURS OR 12 MONTHS OF COMPONENT OPERATION,**

**WHICHEVER OCCURS FIRST. 35**

**10. 7-10. EACH 24 MONTHS OF COMPONENT OPERATION. 36**

**(Includes Corrosion Inspection)**

**2-9. CONDITIONAL INSPECTIONS (AIRFRAME) (CHAPTER 8)**

Inspections required as a result of unusual events such as hard landings
or sudden stoppage of rotor.

PAGE

**1. 8-1. HARD LANDINGS. 38**

**2. 8-2. SUDDEN STOPPAGE - POWER ON OR OFF. 40**

**3. 8-3. OVERSPEED. 44**

**4. 8-4. OVERTORQUE (AIRFRAME AND ENGINE). 46**

**5. 8-5. LIGHTNING STRIKE. 48**

**6. 8-6. MAST BUMPING. 50**

**7. 8-7. AFTER WIRE STRIKE. 50**

**8. 8-8. AFTER LOWER WSPS GROUND CONTACT. 51**

**9. 8-9. AFTER AIRCRAFT IS FLOWN INTO AREA WITH**

**BLOWING SAND AND/OR LOOSE GRASS. 51**

**10. 8-10. AFTER WASHING HELICOPTER. 51**

**11. 8-11. AFTER HELICOPTER SUBJECTED TO SALT WATER/SPRAY. 52**

**12. 8-12. HELICOPTERS OPERATED IN SALT LADEN ENVIRONMENT. 52**

**13. 8-13. AFTER HELICOPTER HAS BEEN PARKED/OPERATED**

**IN RAIN, ICE OR SNOW. 52**

**14. 8-14. AFTER OVERFLOW OF BATTERY/SUMP JAR. 52**

**15. 8-15. TRANSMISSION OIL OVER-TEMPERATURE. 52**

**16. 8-16. COMPLETE LOSS OF TRANSMISSION OIL. 53**

**2-10. CONDITIONAL INSPECTIONS (ENGINE) (CHAPTER 9)**

A Conditional Inspection (Engine) is performed as a result of an unusual
event such as engine oil filter bypass or engine overtemperature.

PAGE

**1. 9-1. FOREIGN OBJECT DAMAGE IS NOTED. 54**

**2. 9-2. SUSPECTED COMPRESSOR STALL OR SURGE. 54**

**3. 9-3. ENGINE IS DROPPED DURING HANDLING. 57**

**4. 9-4. ENGINE SUDDEN STOPPAGE OCCURS. 58**

**5. 9-5. ENGINE OVERSPEED. 58**

**6. 9-6. ENGINE OIL OVERTEMPERATURE. 60**

**7. 9-7. ENGINE SUBJECTED TO EXCESSIVE G-LOADS**

**(HARD LANDING, SEVERE MANEUVERS). 61**

**8. 9-8. ENGINE INLET BLOCKAGE. 62**

**9. 9-9. ENGINE OIL CONTAMINATION. 63**

**10. 9-10. LOSS OF POWER OR HIGH EXHAUST GAS TEMPERATURE. 65**

**11. 9-11. ENGINE OVERTEMPERATURE. 65**

**NOTE**

THERE ARE NO PRESCRIBED INTERVALS FOR THESE INSPECTIONS.

**CHAPTER 3**

**PREVENTIVE MAINTENANCE INSPECTION (P.M.I.)**

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

**SECTION I. GENERAL (SEE INSPECTION SCHEDULE CHART, PAGE 8)**

**1.** Inspect aircraft forms and records for recorded discrepancies.

2.  Ensure all applicable Airworthiness Directives (Safety of Flight,
    Alert Service \|

Bulletin\'s, ASAM's, TM's, TB, MIM's , etc) are complied with. \|

**3.** Review records for SPECIAL or CALENDAR inspection items which are
due.

**4.** Review component listing for overhaul or retirement items which
need to be

replaced.

**5.** Review service instructions for maintenance and inspection
requirements for

installed kits, MWOs and STCs as appropriate. \|

**6.** Perform a general visual inspection of aircraft for condition and

cleanliness.

**7.** Clean the aircraft, particularly the areas being inspected.

**SECTION II. LUBRICATION REQUIREMENTS**

**8.** Refer to applicable UH-1 lubrication chart.

**SECTION III. FORWARD FUSELAGE AREA**

**9.** Inspect nose structure and following components for condition and
security.

**a.** Windshields, nose structure and external equipment.

**b**. Battery compartment structure and components and wiring.

**c.** Pitot and static ports.

**10.** Inspect crew and cargo doors and windows for damage and proper
operation.

**11.** Check cabin exterior for damage. Inspect stencils, decals, and
or placards

for legibility.

**12.** Inspect flight, engine controls and manual cargo release
assembly if

installed.

**13.** Inspect Instrument panel, consoles and installed equipment.

1

**14.** Inspect crew and passenger seats, and seat belts and shoulder
harnesses for

damage and security.

**15.** Inspect navigation, search and landing lights for condition and
check for proper operation.

**SECTION IV. UPPER PYLON**

**16.** Inspect the upper fuselage structure, antennas, cowling and air
intake

screens for debris, damage and security.

**17.** Inspect upper and lower main rotor blade surfaces for damage,
evidence of

corrosion and cracks. Particular attention shall be given to the doubler
area and

all bond lines. Hairline cracks in the paint finish should be inspected
closely

for possible voids.

**18.** Inspect leading edge scarf joints for filler erosion, if splice
cover is not

installed.

**19.** Check main rotor for proper lubricant level, inspect for
evidence of leakage,

and obvious contamination. Not applicable if aircraft is modified with
grease hub. \|

**20.** Inspect main rotor grips for evidence of corrosion and visible
damage.

Inspect shield area for trapped contamination.

**21.** Inspect drag brace attachment lugs for damage, cracks and
security.

**22**. Inspect main rotor hub static stops for obvious deformation
and/or cracks.

**23.** Inspect main rotor yoke for general condition and security of
pillow block

assembly attachment, paying particular attention to the area surrounding
the pillow

block bushing bores. Visually inspect for sealant integrity around yoke
to pillow

block mating surface and around head and nut of yoke to pillow block
attachment

bolt.

**24.** Inspect pillow block bushing flange and outside area of bushing
holes for

evidence of cracks/corrosion.

**25**. Inspect main rotor pitch change links, damper tubes and
connecting links for

scratches, nicks, dents, security of attachment and obviously worn
bearings.

**26.** Inspect mast assembly for obvious damage, particularly in the
area of main

rotor hub static stop contact area.

**27**. Check security of mast nut and mast.

**28.** Inspect mast seal for evidence of leakage.

**29.** Check stabilizer bar dampers for proper fluid level and security
of

attachment.

**30.** Inspect scissors and sleeve assembly for worn bearings and
foreign object damage.

**31.** Inspect swashplate assembly for worn bearings and foreign object
damage.

**32.** Inspect control lugs (3 ea.) on swashplate inner ring and (2
ea.) on swashplate outer ring for cracks.

**33.** Inspect collective levers for security of attachment and foreign
object damage.

**34.** Inspect the transmission and pylon support structure area for
damage, cracks, and leaks.

**35.** Inspect main drive shaft and ensure freewheel unit functions
properly.

**36**. Inspect hydraulic reservoir for proper level, and inspect for
abnormal

oil discoloration.

**SECTION V. LOWER PYLON**

**37.** Inspect transmission oil filter for bypass indication.

**38.** Inspect transmission for proper oil level, and inspect for
abnormal oil

discoloration.

**39.** Inspect transmission mounts and supports for cracks and
security.

**40.** Inspect the transmission tail rotor output quill for grease
leakage and for

over temperature indications.

**41.** Inspect hydraulic system components for damage and leaks, and
the filter for

bypass indication.

**42.** Inspect hydraulic servo cylinder mount nuts for slippage marks.

**43.** Inspect hell hole area for leaks, working fasteners, and general
security of

components. Pay particular attention to the servo/linkage area and the
lift beam

and support case area.

**44**. If external loads are anticipated - Clean and inspect hook
assembly for wear

and damage.

**45.** Inspect landing gear for damage and security. Inspect cross
tubes for visual

indications of excess spread and saddle areas for slippage, cracks and
fretting.

**SECTION VI. ENGINE**

**NOTE**

PERFORM A COMPRESSOR WASH WHEN INSPECTION REVEALS AN ACCUMULATION OF
DIRT, WHEN ENGINE PERFORMANCE DECREASES EXCESSIVELY, AND WHENEVER
EXHAUST GAS TEMPERATURE INCREASES STEADILY DURING NORMAL OPERATION.

**46.** Inspect engine cowlings and fairings for security, damage, and
loose or

missing fasteners.

**47.** Inspect Foreign Object Damage (FOD) screen and particle
separator as follows:

**47.1.** Inspect FOD screen for damage which would permit foreign
object entry.

If screen is damaged inspect compressor for damage. Inspect as outlined
in

**9-1 FOREIGN OBJECT DAMAGE IS NOTED** inspection.

**47.2.** Inspect FOD screen exterior for presence of foreign material.
If

material such as rags, paper, grass or other vegetation is present
enough to

disturb airflow to the inlet perform an inlet blockage inspection in

accordance with **9-8 Engine Inlet Blockage Inspection** of the IPG.

**48.** If the screen or separator is not installed, inspect the inlet
as follows:

**48.1.** Inspect inlet for accumulation of dirt conforming to contour
of inlet

housing. Buildup of dirt may conform to the shape of the inlet housing
and

be difficult to detect. ALL foreign matter must be completely removed.
Any

evidence of inlet blockage shall result in the **9-8 Engine Inlet
Blockage**

**Inspection** of the IPG being performed.

**48.2.** Visually inspect compressor blades, inlet housing air passages
and

variable guide vanes as visible from inlet housing. Inspection shall be
for;

foreign object damage, partial or complete inlet blockage, and salt,
dirt oil

and varnish deposits. If required, perform a compressor wash in
accordance

with the appropriate maintenance manual. Foreign object damage shall be

repaired if it exceeds the limits in the appropriate maintenance manual.

**49.** Inspect droop cam assembly for signs of binding and cleanliness
and linear

actuator for proper operation (except 540 M/R).

**50.** Inspect engine mounts and shims for damage and security.

**51.** Check that oil tank is filled to the proper level. If oil filter
has a

by-pass button, inspect for extension of that button. If button is
extended,

remove and clean filter elements. Reset button and after next flight
check for

extension of the bypass button. If button is found extended, perform an
engine oil

contamination inspection in accordance with **9-9 Engine Oil
Contamination** **Inspection**

of the IPG.

**52.** Inspect power turbine blades through exhaust diffuser and
inspect exhaust

diffuser for, cracks and burnt areas.

**SECTION VII. TAIL BOOM**

**53**. Inspect the tail boom attachment bolt areas for cracks and
security. Pay

particular attention to the upper left attachment area on both the
fuselage and

tail boom. (Check attachment hardware slippage marks).

**54.** Inspect oil cooler blower assembly for cleanliness, blockage and
rough bearings.

**55.** Inspect tail rotor servo for security and leakage.

**56.** Inspect elevators for damage, cracks and looseness.

**57.** Inspect the external portions of vertical splice area, just
forward of

intermediate gearbox, for cracks and corrosion.

**58.** Inspect the external portions of the vertical fin structure for
signs of

fretting, corrosion and cracks.

**SECTION VIII. TAIL ROTOR/DRIVE SYSTEM**

**59.** Clean and inspect tail rotor control chain and sprocket. Inspect
tail rotor cross head for axial and radial movement.

**60.** Inspect intermediate and tail rotor gearbox attachment areas for
signs of

fretting and movement.

**61**. Check intermediate and tail rotor gearboxes for proper oil level
and service

if required. Inspect for abnormal oil discoloration.

**62.** Visually inspect tail rotor drive flex couplings and hanger
assemblies for

overheat indications, grease leakage, security and foreign objects.

**63.** Visually inspect tail rotor blades for damage, cracks, and skin
delamination,

with special attention to the area on both sides between the doublers
and six

inches outboard of doublers.

**CHAPTER 4**

**DETAIL #1 - 50 FLIGHT HOURS**

**\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_**

**SECTION I. GENERAL**

**1.** Perform a P.M.I. Refer to **INSPECTION SCHEDULE CHART, PAGE 8.**

**SECTION II. MAIN ROTOR**

**NOTE**

THE UH-1 INSPECTION PLANNING GUIDE (IPG) WAS DEVELOPED TO PROVIDE
GUIDANCE IN PLANNING INSPECTION PROGRAMS FOR TEN MODELS OF THE UH-1
SERIES HELICOPTER. THE PRIMARY DIFFERENCE\| BETWEEN THE UH-1 SERIES OF
HELICOPTERS ARE THOSE MODELS THAT INCORPORATE THE "540" ROTOR SYSTEM.
COMPONENTS OR PARTS LISTED BY PART NUMBER IN THE UH-1 IPG HAVE SPECIFIC
INSPECTION CRITERIA THAT APPLY TO THAT PARTICULAR PART NUMBER. IN
ADDITION, THE LISTING OF A COMPONENT OR PART, BY PART NUMBER IN THE IPG,
INDICATES THAT DUE TO THE DESIGN OF THAT PARTICULAR COMPONENT OR PART,
SPECIAL ATTENTION IS REQUIRED OF THE REPAIRMAN OR INSPECTOR IN ORDER TO
VERIFY CONTINUED AIRWORTHINESS.

OTHER COMPONENTS OR PARTS, NOT LISTED BY PART NUMBER IN THE UH-1 IPG, DO
NOT REQUIRE SPECIAL ATTENTION OR INSPECTION OTHER THAN WHAT IS CALLED
FOR IN THE UH-1 IPG OR REFERENCED MANUALS.

**2.** Inspect stabilizer bar assembly for visual damage in the form of
scratches,

nicks, dents, cracks, corrosion, and worn bearings.

**2.1.** Inspect stabilizer tubes, 204-011-328-001, -011, for cracks,
paying

particular attention to an area covering 360 degrees and 1-1/2 inches

outboard from vertical bolt.

**3.** Inspect main rotor drag braces for evidence of corrosion and
security of

attachment. Make a close visual examination of inboard end (grip end) of
drag

brace assembly for corrosion and/or cracks.

**4.** Check torque on main rotor pillow block bolt nuts 64 to 79
foot-pounds. Do

not loosen nut. Apply sealant, as required, to area in accordance with
applicable

manual.

**SECTION III. PYLON**

**5.** Inspect swashplate gimbal ring joint.

**NOTE**

DO NOT ATTEMPT TO TURN BOLTS. BOLT MOVEMENT WILL FAIL LOCTITE BOND AND
CAUSE BOLT WEAR.

**5.1.** Grasp swashplate rotating ring (204-011-403) and attempt to
move it in

a horizontal plane on an axis in line with gimbal ring attach points to

support assembly (204-011-404). Maximum allowable axial looseness across

the gimbal ring bearings and attaching bolts is 0.010 inch.

**5.2.** Repeat subparagraph **5.1**., on axis 90 degrees to the check
in

subparagraph **5.1**., attempt to move it in a vertical plane to detect
looseness

in line with gimbal ring attach points in inner ring (204-011-402).
Maximum

allowable axial looseness across the gimbal ring bearings and attaching
bolts

is 0.010 inch.

**5.3.** Inspect swashplate trunnion bearings for wear and security. For

204-011-451 trunnion: Disconnect scissors drive links from trunnion and

check swashplate bearing for roughness, binding and vertical play.
Rotate

and lubricate trunnion before reconnecting.

**SECTION IV. TRANSMISSION**

**6.** Inspect web above input quill for cracks. Any indication of a
crack is

cause for removal of case.

**7.** Inspect internal filter and chip detector. If metallic chips or
particles ****

are found, investigate to determine cause.

**8**. Inspect oil lines and hoses for pin holes or cracks due to
chafing.

**9.** Inspect oil line quick disconnect for leaks, wear and proper pin
engagement.

**10.** Inspect wire bundles and controls for chafing.

**11.** Check oil sight gage for discoloration and contamination.

**12.** Inspect transmission tail rotor drive quill coupling and main
drive shaft

seals and surrounding area for evidence of grease leakage, visual
overheat

indicator for discoloration and overheat condition. A change in color of

indicator indicates a possible overheat and/or component degradation.
Cause of

discoloration shall be determined and corrected prior to flight.

**13.** Remove and visually inspect generator drive quill magnetic chip
plug for

contaminants.

**14.** Visually inspect generator condition, (Spline wear and brush
inspection is

performed during the Special Inspection, **7-9. EACH 600 HOURS OR 12
MONTHS OF**

**COMPONENT OPERATION, WHICHEVER OCCURS FIRST:** of the IPG).

**15.** Perform an operational check of transmission chip detector
system.

**SECTION V. FUSELAGE (PYLON AREA)**

**16.** Inspect fuselage pylon structure for cracks, distortion, missing
rivets.

Inspect transmission support for cracks, distortion, defective/missing
rivets.

Inspect lift beam assembly for cracks.

**17.** Inspect friction dampers. Move pylon fore and aft, using mast as
lever.

Check friction dampers for freedom of movement and smooth operation.
Repair or

replace dampers found binding.

**18.** Inspect isolation mounts, mount boots, mounting brackets and
structure for

cracked or broken parts.

**19.** Inspect fifth mount attachment for damage and security. Inspect
mount and

support beam for cracks.

**20.** Inspect lift link, lift beam fitting and lower sump case
attachment for

security and cracks.

**NOTE**

REFER TO PAGE 5, **NOTE**, FOR REPETITIVE LIFTS.

**SECTION VI. HYDRAULIC SYSTEM**

**21.** Inspect all lines, fittings and hoses for leakage and security,
kinks,

general condition, and pitting. Pay particular attention to the
condition of the

hoses.

**22.** Inspect hydraulic actuators for leakage and security. Clean
exposed area of

cylinder piston with hydraulic fluid and lint free cloth.

**23.** Inspect actuator attachment brackets for security, cracks, and
corrosion in

immediate area.

**24**. Inspect pump for damage and leakage.

**SECTION VII. TAIL ROTOR/DRIVE SYSTEM**

**25.** Perform operational check of intermediate and tail rotor gearbox
chip

detector system.

**26.** Check torque of intermediate gearbox attachment bolts; and check
torque of

tail rotor gearbox retaining nuts. Do not loosen bolts/nuts.

**27.** Inspect tail rotor pitch change mechanism as follows:

**27.1.** Mount dial indicator on tail rotor gearbox output shaft with
dial

indicator lever on outboard edge of crosshead adjacent to pitch link
bolt.

**27.2.** Apply and hold full left pedal. Move crosshead in a radial
(rocking

motion) and note amount of maximum radial movement. Maximum movement
should

not exceed 0.020 inch.

**27.3.** Apply and hold full right pedal. Perform check as stated in

subparagraph **27.2**, above. Maximum movement should not exceed 0.035
inch.

**27.4.** If tolerances stated in subparagraphs **27.2** and **27.3**
are exceeded,

inspect inner splines of tail rotor crosshead slider and mating splines
on

tail rotor gearbox output shaft.

**27.5.** Place control pedals in neutral position. Move crosshead in
axial

direction (in and out), being careful not to cause radial movement.
Maximum

movement should not exceed 0.018 inch.

**27.6.** If tolerance in subparagraph **27.5** above, is exceeded,
inspect crosshead

bearings, control quill bearings and acme thread of control tube and
mating

threads in control nut.

**CHAPTER 5**

**DETAIL #2 - 100 FLIGHT HOURS**

**\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_**

**SECTION I. GENERAL**

**1.** Perform a P.M.I. See **INSPECTION SCHEDULE CHART, PAGE 8.**

**SECTION II. FORWARD FUSELAGE AREA**

**2.** Inspect landing gear for wear of skids and shoes, security of
mountings for

skids and crosstubes. Inspect skid tubes and crosstubes for cracks,
distortion, or

yielding.

**3.** Inspect fuselage exterior structure for cracks, dents, corrosion,
defective

and missing rivets or screws.

**SECTION III. PILOT AND PASSENGER COMPARTMENTS**

**4.** Check all safety equipment for inspection due dates and
operation.

**5.** Inspect all heating and cooling ducts and controls for cracks,
security, and

operation.

**6.** Inspect cabin structure for cracks, loose rivets and other
damage.

**7.** Functionally check crew door mechanism and jettison mechanism,
and inspect

for wear, corrosion and distortion. Inspect hinges for cracks.

**8.** Inspect seat adjustment mechanism and tracks for wear, positive
locking and

lubrication.

**9.** Functionally check cargo door window jettison mechanism.

**10.** Inspect cargo door latching mechanism and door rollers for wear
and damage.

**11.** Drain pitot static system, if necessary.

**SECTION IV. LOWER PYLON, ENGINE and AFT/CENTRAL AREA**

**12**. Inspect lift beam and surrounding area for cracks and working
rivets.

**NOTE**

SEE PAGE 5, **NOTE,** FOR REPETITIVE LIFTS.

**13.** Inspect droop compensator shear pin.

**14.** Inspect fuel cell X-connector, surrounding structure, and fuel
lines for

condition.

**15.** Check engine idle solenoid for operation, freedom of plunger,
inspect for

corrosion and security. Check for proper clearance.

**16.** Inspect bleed air discharge line for chafing and blockage.

**17**. Inspect voltage regulator for damage and security of mounting
and terminals.

**18**. Inspect relays and main bus area for security of mounting and
connections.

**SECTION V. FLIGHT CONTROLS**

**19.** Inspect all control rods for clearance, security and general
condition.

**20.** Inspect tail rotor and synchronized elevator control tubes for
wear.

**21.** Check all controls for freedom of motion.

**22.** Check collective stick for proper minimum friction. Check shoes
and liners

for excessive wear.

**23.** Check collective sleeve mast friction collet for proper minimum
friction

(540 M/R).

**24.** Check swashplate uniball for proper minimum tilt friction (540
M/R).

**SECTION VI. TAIL ROTOR**

**25.** Dynamically track and balance.

**CHAPTER 6**

**DETAIL #3 - 150 FLIGHT HOURS**

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**SECTION I. GENERAL**

**1.** Perform a P.M.I. **SEE INSPECTION SCHEDULE CHART, PAGE 8.**

**SECTION II. MAIN ROTOR**

**2**. Check torque on the 8 bolts attaching stabilizer bar supports to
trunnion.

**SECTION III. TAIL ROTOR**

**3**. Inspect tail rotor hub assembly for worn bearings.

**4**. Clean tail rotor blades to maintain improved visibility.

**5.** Clean and inspect tail rotor control chain and aft cables for
wear,

corrosion, cracks, broken strands and proper tension.

**SECTION IV. TAIL ROTOR DRIVE SECTION**

**6**. Inspect intermediate and tail rotor gearbox sealants for
condition and re-seal

as needed.

**7**. Inspect both gearbox vents and filler cap packing for condition.

**8**. Check condition of clamps for tail rotor shaft coupling to
gearbox couplings.

Inspect clamps for evidence of cracks in or near the bolt hole lugs.

**9**. Externally examine shaft hanger bearings and shaft couplings for
evidence of

grease leakage, overtemperature condition, and excessive play and/or
movement.

**SECTION V. TRANSMISSION **

**10.** Remove and inspect the external oil filter (paper filter) for
metal chips or ****

particles, investigate to determine cause if metal chips are found, and
replace ****

with new filter element. ****

**SECTION VI. TAIL BOOM**

**11**. Inspect internal and external structure of tail boom for cracks,
distortion,

corrosion and security.

**12**. Visually inspect all tail boom attachment fittings for cracks
and security

as follows:

**NOTE**

ANY CRACK, CORROSION, OR BOND SEPARATION IS CAUSE FOR IMMEDIATE
GROUNDING OF AN

AIRCRAFT UNTIL THE PROBLEM HAS BEEN ELIMINATED.

**12.1.** Using a bright light and mirror, inspect visible portions of

attachment fittings for cracks. Special attention must be given to upper

left attachment fitting, particularly in area of most forward rivets.

Inspect longeron, left and right sides, from attachment fittings to next
aft bulkhead for any evidence of corrosion.

**12.2**. Remove access panels on lower skin of tail boom to expose
lower

attachment fittings. Using a bright light and mirror, inspect visible

portions of attachment fittings for any indications of cracking,
particularly

in area of most forward rivets. Inspect longeron left and right sides,
from

attachment fittings to the next aft bulkhead, for any evidence of
corrosion.

**12.3.** Remove access plugs at bore for barrel nuts and visually
inspect

tail boom attachment fittings. Check torque of tail boom attachment
bolts.

**DO NOT BACK OFF NUTS.** Be sure that no less than one, nor more than
three

threads protrude through the barrel nut.

**12.4**. Open access door on right side of fuselage and inspect the
four tail

boom attachment fittings on fuselage aft bulkhead for cracks giving
special

attention to the area around tail boom attachment bolts and most aft

fasteners. Particular attention must be given to inspection of left hand

fittings.

**13**. Inspect vertical fin rib along rivet row at fin station 10.08
for cracks,

(tail rotor 90 degree gearbox casting area accessed through topmost
lightning

holes).

**14**. Inspect vertical skin splice area at boom station 194.3, just
forward of

intermediate gearbox, for cracks and corrosion.

**15.** Inspect tail rotor gearbox support casting for cracks and
corrosion.

**16**. Inspect tail rotor and synchronized elevator push-pull tubes for
chafing,

cracks and corrosion.

**17**. Inspect tail rotor control cables and pulleys for wear, damage,
chafing,

corrosion or fraying.

**18**. Inspect elevator and horn assembly for security, condition, and
corrosion.

**SECTION VII. ENGINE**

**NOTE**

FOR ENGINES WITH PARTICLE SEPARATOR AND FOD SCREENS INSTALLED, PERFORM
PARAGRAPH 18., BELOW. IF THERE IS NO PARTICLE SEPARATOR OR SCREEN,
PERFORM PARAGRAPH 19., BELOW.

**19**. Remove particle separator. Clean and inspect seals and gaskets
for tears,

separations of material, cracks in the separator and other damage.

**20**. Visually inspect compressor blades and inlet housing air
passages and

variable guide vanes as required in the IPG, **Chapter 3, P.M.I**.,
**Section VI.,**

**ENGINE**, Paragraph **48.**

**21**. Inspect starter and mounts for security of mounting, burned or
arced

connections, and cooling air ducts for obstructions, kinking and
security.

(Spline wear and brush inspection is performed during Special
Inspection,

**22**. Inspect engine mounts for security, and tubes for scratches,
dents, cracks,

and worn bearings.

**23**. Inspect engine bleed air actuator strainer for condition and
cleanliness.

Clean if required. Inspect bleed band assembly for bends, cracks and
security.

**24**. Inspect air diffuser for security and damage:

**24.1.** Inspect brazed joints including vanes brazements for cracks.
Inspect

brazed joints of air outlet pan (P3) fitting for cracks. Inspect engine

mounts for security and cracks. Refer to the manufacturer's maintenance

manual for repair procedures.

**25**. Functionally check anti-ice valve.

**26**. Inspect and clean fuel control inlet strainer.

**27**. Inspect and clean/replace fuel control servo strainer and
replace paper

filter if installed.

**28**. Replace main fuel filter element.

**29**. Inspect and functionally test chip plug.

**30**. Inspect and clean engine oil filter assembly.

**31**. Inspect quick disconnects and breakaway fittings for security
and wear.

**32**. Inspect engine decks for damage and de-bonding.

**33**. Inspect deck drain holes and channels for obstruction.

**34**. Inspect N1 controls for wear and binding. Verify fuel control
lever contacts

stops with both pilot and co-pilot twist grips. Check idle detent
operation and

condition.

**35**. Inspect N2 controls for wear and binding. Verify pin condition.

Functionally test linear actuator for proper operation.

**36**. Functionally test heater actuator valve.

**37**. Inspect bleed air lines and fittings for wear and blockage.

**38**. Inspect engine wiring harness for chafing, loose or corroded
connections.

**39**. Inspect ignition exciter and leads for damage, chafing, and
security.

**40**. Inspect oil lines and hoses for damage, chafing, leakage, and
security.

**41**. Inspect fuel lines and hoses for leakage, chafing and security.

**42**. Inspect combustion chamber housing, support cone, fire shield,
and exhaust

diffuser for cracks, hot spots, burned areas, and buckling.

**43**. Through the aft end of the combustion housing, inspect for
missing and cracked ****

power turbine blades or cracks in the exhaust diffuser.

**44.** Inspect the remainder of engine for condition. Inspection shall
include but

not be limited to items such as; corrosion of magnesium parts, fasteners
not torqued properly, oil or fuel leaks found on accessories or their
hoses. All discrepancies shall be inspected to the limits found in the
appropriate maintenance manual.

**CHAPTER 7**

**SPECIAL INSPECTIONS**

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In addition to the P.M.I. and the Detail #1, #2, and #3 Inspections,
Special Inspections are performed on a calendar basis, a combination of
hourly/calendar basis, or following the installation of major components
such as the intermediate gearbox.

**7-1. AFTER EACH INSTALLATION**

**1.** Dynamic balance and track tail rotor hub and blade assembly.

**2.** Perform an in flight track and balance of the main rotor
assembly, if main rotor hub maintenance has been performed or the main
rotor blades have been replaced.

**7-2. AFTER FIRST FLIGHT, AFTER EACH INSTALLATION**

**1.** Main drive shaft Bell Helicopter Textron (BHT Shaft) - Inspect
drive shaft for

excessive grease leakage, security and condition.

**2.** Tail Boom - Check torque of attachment bolts. Do not loosen
bolts.

**3.** Scissors and sleeve collective mast friction collet (540 M/R) -
Check friction

as outlined in applicable manual.

**7-3. BETWEEN 5 AND 10 HOURS, AFTER EACH INSTALLATION**

**1.** Main rotor hub - Check torque of hub retention nut. Do not loosen
nut.

**2.** Tail rotor hub - Check torque of tail rotor retaining nut. Do not
loosen nut.

**3.** Tail rotor control chain and/or sprocket. Check control cable
tension and

adjust as required.

**4.** Intermediate gearbox - Check torque of gearbox attachment bolts.
Do not loosen bolts.

**5.** Tail rotor gearbox - Check torque of gearbox retaining nuts. Do
not loosen nuts.

**7-4. EACH 25 HOURS OF OPERATION**

**1.** 540 M/R main rotor hub - Inspect feathering bearings for
squeaking, binding

and ratcheting while feathering grips to each limit of travel, with
pitch change

links disconnected (one grip at a time). Remove sand defector for a more
detailed visual inspection of feathering bearings for deteriorated or
loose Teflon lining. Inspect Teflon trunnion bearings for squeaking,
binding and ratcheting while flapping hub to each limit of travel.

***WARNING:***

***DO NOT FLAP THE ROTOR HARD AGAINST THE MAST.***

**7-5. EACH 100 HOURS OR 120 DAYS, WHICHEVER OCCURS FIRST**

**1.** Voltage regulator - Check voltage regulator setting.

**7-6. 100 HOURS AFTER EACH INSTALLATION**

**1.** Tail boom - Check torque of attachment bolts. Do not loosen
bolts.

**7-7. 300 HOURS OR 6 MONTHS OF BATTERY OPERATION**

**1.** Remove NICAD battery, check capacity and perform re-conditioning
cycle, if necessary, in accordance with the battery manufacturer's
instructions.

**7-8. EACH 12 MONTHS MAGNETIC (MAG) COMPASS AND RADIO MAGNETIC
INDICATOR (RMI)**

**CALIBRATION**

**1.** Verify calibration of MAG compass and the RMI.

**2.** Correct as necessary and update calibration placards.

**7-9. EACH 600 HOURS OR 12 MONTHS OF COMPONENT OPERATION, WHICHEVER
OCCURS FIRST:**

**1.** Battery overtemperature - Perform operational check of battery

temperature system (if installed). (Refer to the manufacturers
instructions).

**2.** Emergency Locator Transmitter (ELT) - Functionally check ELT

(if installed) and replace batteries if expired.

**3.** Oil Cooler - Remove oil cooler screens and clean fan blades and
assembly.

Check bearings for roughness and binding. Inspect cooler for
obstructions and

leaks.

**4.** Main Drive Shaft (KAFLEX) - Remove drive shaft and inspect
internal fail-

safe diameters for evidence of contact. If contact is noticed, drive
shaft

must be replaced. Visually inspect drive shaft for obvious mechanical
damage,

flexplate looseness, corrosion, and/or fretting at flex plate bolted
joints.

**4.1** Main Drive Shaft (BHT) - Remove drive shaft and clean, inspect,

lubricate and reassemble in accordance with applicable TM.

**5.** Starter/Main Generator **-** Remove starter generator and;
inspect accessory

gearbox generator drive splines for wear and lubricate, inspect the
starter

generator splines for wear and lubricate, and inspect the starter
generator brushes

for wear.

**6.** Lead Acid Battery - Check for proper fluid level and condition in

accordance with battery instruction manual.

**7.** Drain transmission and transmission oil cooler. Inspect and clean

transmission oil pump screen. Inspect and functionally check chip plug.
Replace

external filter. Service transmission with oil.

**8.** Drain engine oil and engine oil cooler. Inspect and functionally
check

chip plug. Replace external filter. Service engine with oil.

**9.** Drain intermediate gearbox oil. Inspect and functionally check
chip plug.

Service gearbox with oil.

**10.** Drain tailrotor gearbox oil. Inspect and functionally check chip
plug.

Service gearbox with oil.

**11.** Replace hydraulic filter element(s).

**12.** Remove and inspect all tail rotor flex couplings for cracks and
condition of internal splines and couplings. ****

**7-10. EACH 24 MONTHS OF COMPONENT OPERATION**

**1.** Perform functional check of the Pitot Static System.

**2.** Main rotor yoke - Remove, dissemble and inspect main rotor hub as
follows: Remove bearing races, spacers, and radius rings from yoke
spindles. Inspect yoke spindle for cracks and corrosion pits, paying
particular attention to the inboard radius of the spindle. Inspect yoke
center section for cracks, paying particular attention to areas
surrounding the pillow block bushing bores. Any crack is cause for
rejection of the yoke. Clean up any corrosion. Replace tension torsion
straps if calendar life is expired. Reassemble hub using new pillow
block attaching hardware.

**3**. Main rotor mast - Inspect inside and outside diameters of mast
for corrosion

and mechanical damage.

**4.** Airframe - The operator will perform a thorough and searching
airframe

inspection to find and preclude airframe deterioration. This inspection
will

provide the operator with a structural evaluation to determine if the
airframe has

aged to a point that major refurbishment is necessary. Using the
applicable model

TM for damage and repair limits, accomplish the following:

**4.1.** Inspect forward and aft upper and lower cargo door tracks for
wear and

cracking.

**4.2.** Inspect cargo door rollers and guides for wear.

**4.3.** Inspect cabin door post(s) vertical angles for cracks.

**4.4.** Inspect following honeycomb panels for delamination, voids,
surface

damage (dents, punctures) and corrosion:

**a.** Forward fuselage, main beams under cabin floor.

**b.** L/H and R/H pylon island panels.

**c.** Aft cabin bulkhead panels.

**d.** Transmission and engine work/service deck panels.

**e.** Roof deck panels.

**f.** L/H and R/H aft outboard fuel cell bulkheads.

**g.** L/H and R/H lower outboard fuel cell panels.

**h.** L/H and R/H aft main beam panels (viewed through fuselage

compartment doors).

**i.** Forward main fuel cell panel and aft center fuselage panel

(viewed in hell hole area).

**5.** Inspect following areas for cracks, corrosion, and loose or
working rivets.

**a.** Pylon lift bean webs and lift link fitting.

**b.** Pylon structure.

**c.** Aft fuselage lower skin.

**d.** Aft fuselage tail boom attachment fittings and longerons.

**e.** Tail boom and vertical fin interior and exterior skin, fuselage

attachment fittings and longerons.

**f.** Intermediate and tail rotor gearbox castings.

**6.** Inspect electrical wire bundles in main fuselage and tail boom
for oil and

hydraulic fluid soaked insulation, discolored wire indicating
overheating,

cracked or broken insulation.

**CHAPTER 8**

**CONDITIONAL INSPECTIONS (AIRFRAME)**

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Conditional Inspections found in Chapter 8 are inspections required as a
result of unusual events such as a hard landing or sudden stoppage of
rotor.

**8-1. HARD LANDING** - Hard landing is defined as any accident or
incident in which ground impact of the helicopter causes severe pitching
of main rotor, allowing hard contact of hub with mast, or results in
yielding or cracking the mounting lugs of the transmission support case
or noticeable yielding or cracking of fuselage pylon support structure
or landing gear. This definition is confined only to those accidents or
incidents not involving sudden stoppage of main rotor or tail rotor.

**NOTE**

COMPONENTS REMOVED FROM A HELICOPTER FOLLOWING A HARD LANDING SHALL BE
EVALUATED AS AN INTERRELATED GROUP. REMOVAL RECORDS ACCOMPANYING EACH
COMPONENT SHALL CROSS REFERENCE PART AND SERIAL NUMBERS OF OTHER DRIVE
SYSTEM COMPONENTS REMOVED FOR EVALUATION.

**If a hard landing is suspected, the following Paragraphs 1 through 6
below, shall be accomplished.**

**1.** Inspect main and tail rotor blades for evidence of strike damage.
If

such evidence is found on either rotor, perform **8-2. SUDDEN STOPPAGE -
POWER**

**ON OR OFF INSPECTION,** of the IPG**.**

**2.** Visually inspect underside of fuselage and tail boom for evidence
of

ground contact.

**3.** Perform landing gear deflection check.

**3.1.** If crosstubes have yielded, remove landing gear and inspect
support and

structure to which they are attached for signs of yielding or other
damage.

**3.2.** If supports and attaching structure are not damaged, replace
damaged

landing gear components.

**4.** Inspect mast for deformation due to rotor hub contact.

**4.1.** Inspect area around lower supports of pylon dampers for loose
rivets or

other damage.

**5.** If no damage other than yielded landing gear crosstubes has been
found at this point it can reasonably be determined that a true hard
landing did not occur. Complete a P.M.I. and return helicopter to flight
status provided no further evidence of damage is found.

**6.** If damage is more extensive than landing gear crosstube yielding,
**a hard landing has occurred, the following Paragraphs 7 through 21
below, shall be accomplished:**

**7**. Remove and perform an overhaul evaluation inspection of the
following

components.

**a.** Mast assembly.

**NOTE**

IF THERE IS ANY DEFORMATION IN AREA CONTACTED BY MAIN ROTOR HUB, OR ANY
OTHER OBVIOUS DAMAGE, THE MAST IS NOT AIRWORTHY AND IS UNSERVICEABLE.

**b.** Transmission.

**c.** Main input drive shaft. (Grease lubricated type.)

**8.** Perform a thorough visual inspection of the following components,
which

may be kept in service if no discrepancy or obvious damage is found.
Replace

any damaged component.

**a.** Main rotor blades.

**b.** Main rotor hub.

**c.** Tail rotor blades.

**d.** Tail rotor hub.

**e.** Anti-torque controls.

**f.** Intermediate gearbox.

**g.** Tail rotor gearbox.

**h.** Tail rotor drive shafts.

**i.** Tail rotor drive shaft hangers.

**j.** Swashplate and support assembly.

**k.** Scissors and sleeve assembly.

**l.** Stabilizer bar assembly.

**m.** Main rotor controls.

**n.** Visually inspect KAFLEX drive shaft for the following

conditions:

**(1)** Bolt contact with adjacent plate(s).

**(2)** Plate contact with end fitting(s).

**(3)** Interconnect contact with end fitting(s).

**(4)** Contact of fail-safe surface(s).

**NOTE**

IF ANY OF THE CONDITIONS DESCRIBED IN SUBPARAGRAPHS n., (1) THROUGH (4)
ABOVE ARE FOUND, REPLACE KAFLEX SHAFT.

**9.** Check all cowling and doors for proper fit and alignment. Remove

cowling and inspect all attachment fittings.

**NOTE**

IF SIGNIFICANT DAMAGE HAS BEEN FOUND IN ANY AREA OF THE AIRFRAME,
INSPECTION SHALL BE EXPANDED BEYOND THE ZONE OF DAMAGE.

**10.** Using 10-power magnifying glass make a complete inspection of
pylon support structure for loose or sheared rivets, cracked brackets,
buckled or cracked support angles or webs. Pay particular attention to
pylon mounts attaching points and damper support attaching points.

**11.** Remove lift link and make a complete inspection of lift link,
lift link

attachment fittings and lift beam for cracks and other evidence of
damage. If

lift link is damaged it is not airworthy and is unserviceable.

**12.** Remove both pylon dampers, disassemble and check for internal
yielding.

Reassemble and reinstall if no evidence of damage. If pylon dampers have

yielded they are not airworthy and are unserviceable.

**13.** Install serviceable mast, transmission assembly and main drive
shaft

assembly. Re-install removed pylon control components.

**14.** Check all engine mount fittings and bolts for damage and
looseness.

**15.** Inspect engine firewalls for evidence of warping, crushing, or
other damage.

**16.** Make a complete inspection of area where tail boom is attached
to

forward fuselage section. This includes both sets of attachment fittings
and

the longerons, beam caps, skins, webs, bulkhead flanges and other
structural

members. Check torque on attachment bolts to determine if yielding has
occurred.

**17.** Completely inspect flight control system from pilots controls to
rotor

head for bent or damaged tubes, bellcranks, bellcrank supports and for
damage to

control system bearings. Particular attention shall be given to pylon
controls,

lower cylinder attachment support fitting and adjacent airframe
structure.

**18.** Pressurize hydraulic system and check for leaks, interference,
binding

and for satisfactory operation.

**19.** Inspect fuel, oil and pneumatic system for damage, perform
engine ground

run and visually check fuel, oil and pneumatic lines for leaks.

**20.** Inspect wire strike protection system (WSPS) as follows:

**20.1.** Inspect lower assembly for obvious damage to WSPS and
attachment

area for damage.

**20.2.** Inspect windshield deflector and upper WSPS assembly for
obvious damage

to WSPS and attachment area for damage.

**21.** Inspect power plant in accordance with engine manufacturer's
inspection

guide.

**NOTE**

IF NO SIGNIFICANT DAMAGE HAS BEEN FOUND, NO FURTHER INSPECTION IS
NECESSARY.

**8-2. SUDDEN STOPPAGE - POWER ON OR OFF.** Sudden stoppage is defined
as any rapid

deceleration of the drive system whether caused by seizure within the
helicopter

transmission or by contact of the main or tail rotor blades with the
ground, water,

snow, dense vegetation or other object of sufficient inertia to cause
rapid

deceleration. Main or tail rotor blade damage, when caused by striking
some object

sufficient to require blade replacement, is considered sudden stoppage.
When

sudden stoppage occurs, inspect helicopter and replace components as
follows:

**NOTE**

COMPONENTS REMOVED FROM A HELICOPTER, FOLLOWING A SUDDEN STOPPAGE, SHALL
BE EVALUATED AS AN INTERRELATED GROUP. REMOVAL RECORDS ACCOMPANYING EACH
COMPONENT SHALL CROSS REFERENCE PART AND SERIAL NUMBERS OF OTHER DRIVE
SYSTEM COMPONENTS REMOVED FOR EVALUATION.

Perform a sudden stoppage inspection as follows:

**NOTE**

IF SUDDEN STOPPAGE INSPECTION IS THE RESULT OF A TAIL ROTOR STRIKE,
COMPLY WITH

**8-2. SUDDEN STOPPAGE - POWER ON OR OFF,** PARAGRAPHS **7.** through
**12**., BELOW.

**1.** Main rotor blades.

**1.1.** Visually inspect both main rotor blades for evidence of damage.
Check closely

for wrinkled skin.

**1.2.** If either blade is damaged sufficiently to require blade
replacement, return

both blades to an authorized overhaul facility. Make an entry in
component record to

show that reason for removal was Sudden Stoppage.

**1.3.** If no evidence of damage is found on either blade, both blades

may be returned to service.

**2.** Main rotor hub.

**2.1.** If main rotor blades were not damaged, the main rotor hub may
be

returned to service.

**2.2.** If main rotor blades were damaged sufficiently to require blade

replacement, perform an overhaul evaluation inspection on main rotor hub

assembly. Make an entry in component records to show that reason for

removal was Sudden Stoppage

**2.3.** If any main rotor blade is damaged beyond repair, grip is
unserviceable

and not airworthy. Perform overhaul evaluation inspection on main rotor
hub.

Make an entry in component record to show that reason for removal was
Sudden

Stoppage.

**3.** Pylon control components.

**3.1.** If one or more of the following discrepancies in subparagraphs
**a**.

through **e.** below are found, the swashplate assembly, stabilizer bar

assembly, and scissors and sleeve assembly shall be removed and an

overhaul evaluation shall be performed.

**a.** Severe main rotor blade damage.

**b.** Pitch horn failure.

**c.** Yielded stabilizer bar tube.

**d.** Control tube buckled or broken.

**e.** Transmission main support case mounting leg broken.

**3.2.** Using a ten-power magnifying glass, make a complete inspection
of

pylon support structure for loose or sheared rivets, cracked support

angles and webs. Pay particular attention to pylon mounts attaching

points and damper support attach points.

**3.3.** If no condition exists as listed in preceding subparagraph
**3.2**., above,

perform a close visual inspection and if no evidence of damage is found,

the swashplate assembly, stabilizer assembly, and scissors and sleeve

assembly may be returned to service.

**4.** Replace all bolts in rotating controls. Discard removed bolts.

**5.** Remove and inspect main drive shaft visually. If evidence of
yielding or

deformation is noted, scrap the drive shaft assembly. If no visual
evidence of

damage is detected, perform an overhaul evaluation. Make an entry in

component record to show that the reason for removal is Sudden Stoppage.

**OR** Visually inspect KAFLEX drive shaft for the following conditions:

**a.** Bolt contact with adjacent plate(s).

**b.** Plate contact with end fitting(s).

**c.** Interconnect contact with end fitting(s).

**d.** Contact of fail-safe surface(s).

**NOTE**

IF ANY ONE OF THE ABOVE CONDITIONS IN PARAGRAPH **5, a**. THROUGH
**d**., ARE FOUND, REPLACE SHAFT. RETURN SHAFT TO SERVICE IF NO DAMAGE
IS FOUND.

**6.** Transmission and mast assembly.

**6.1.** If mast has evidence of torsional yielding, the mast and

transmission shall be considered unserviceable and scrapped.

**6.2.** If mast does not have torsional yielding and transmission has

no obvious damage that would render it unserviceable, then transmission

and mast shall have an overhaul evaluation performed. Make an entry in

component record to show that the reason for removal was Sudden
Stoppage.

**7.** Tail rotor drive shaft hangers.

**7.1.** If a tail rotor drive shaft section has been damaged by main
rotor

strike or other circumstances, the hangers to which the damaged section

was attached shall be considered unserviceable and not airworthy. If a
tail

rotor drive shaft fails as a result of torsional load then all hangers
and

sections shall be considered unserviceable and not airworthy. Make a

complete inspection of area where tail boom is attached to forward
fuselage

section. This includes all attachment fittings and the longerons, beam
caps,

skins, webs, bulkhead flanges and other structural members. Check torque
on

attachment bolts to determine if yielding has occurred.

**7.2.** If no damage is found in the preceding subparagraph **7.1**,
overhaul the

bearings in accordance with the applicable maintenance manual. Make an
entry

in component record to show that the reason for removal was Sudden
Stoppage.

**8.** Tail rotor drive shaft.

**8.1.** Remove all tail rotor drive shaft sections and inspect for the
following

conditions listed below. If one or more conditions listed in
subparagraphs

**a.,** through **e.,** below, are noted, all drive shaft sections and
bearing

hangers shall be considered unserviceable and not airworthy. Make a
complete

inspection of area where tail boom is attached to forward fuselage
section.

This includes both sets of attachment fittings and the longerons, beam
caps,

skins, webs, bulkhead flanges and other structural members. Check torque
on

attachment bolts to determine if yielding has occurred.

**a.** Curvic faces distorted.

**b.** Evidence of overload.

**c.** Cracks.

**d.** Loose or sheared rivets.

**e.** Scratches in excess of limits. (Refer to applicable Model TM.)

**8.2.** If inspection reveals no condition as listed in subparagraphs
**8.1.,a.**

through **e**., above exists, then perform an inspection in accordance
with

applicable TM. Make an entry in component record to show that the reason
for

removal was Sudden Stoppage.

**9.** Tail rotor hub and blade assembly.

**9.1.** If sudden stoppage originated at tail rotor blades, the tail
rotor hub

and blade assembly shall be considered unserviceable and not airworthy.

**9.2.** If sudden stoppage originated at main rotor or transmission,
the tail

rotor hub and blade assembly may remain in service provided there is no

visible external damage. If visible damage is noted on tail rotor hub
and

blade assembly; remove tail rotor hub and blade assembly and perform
overhaul

evaluation inspection. Make an entry in component records to show that
the

reason for removal was Sudden Stoppage. The tail rotor grips and blade

attachment bolts must be considered unserviceable and not airworthy.

**9.3.** If sudden stoppage originated at tail rotor drive shaft,
intermediate

gearbox or tail rotor gearbox, remove tail rotor hub and blade assembly
and

perform overhaul evaluation inspection. Make an entry in component
record to

show that the reason for removal was Sudden Stoppage.

**10.** Tail rotor gearbox.

**10.1.** Remove tail rotor gearbox. Check for cracks, sheared or bent
attaching

studs and evidence of case distortion. If any of the listed is noted,
then

the gearbox is not airworthy and is unserviceable.

**10.2.** If no damage is found in the preceding subparagraph **10.1.,**
above,

overhaul the gearbox in accordance with the applicable overhaul manual.

Make an entry in component record to show that the reason for removal
was

Sudden Stoppage.

**11.** Intermediate gearbox.

**11.1.** Remove intermediate gearbox. Inspect for cracks, case
distortion or

broken lugs. If any of the above is noted then the gearbox is not
airworthy

and is unserviceable.

**11.2.** If no damage is found in the preceding subparagraph **11.1.**,
overhaul the

gearbox in accordance with the applicable overhaul manual. Make an entry

in component record to show that the reason for removal was Sudden
Stoppage.

**NOTE**

IF NO EVIDENCE OF DAMAGE WAS FOUND IN HEADING **8-2.,** PARAGRAPH **7.**
THROUGH **11.,** ABOVE, THEN OMIT HEADING **8-2.,** PARAGRAPH **12.,**
BELOW**.**

**12.** Transmission sump case.

**12.1.** If damage was found on bearing hangers, tail rotor drive
shaft,

intermediate gearbox or tail rotor gearbox, then remove tail rotor drive

output quill from transmission sump case assembly.

**12.2.** Inspect output quill pinion for unusual load patterns on both

sides of teeth. If no damage is found; reinstall quill, and transmission
can

be returned to service.

**12.3.** If tail rotor drive quill reveals discrepancies, remove
transmission

and perform an overhaul evaluation. Make an entry in component record to

show reason for removal was Sudden Stoppage.

**8-3. OVERSPEED** - Overspeed is defined as any incident in which 356
main rotor rpm and/or engine overspeed limits in engine manufacturer's
manual are exceeded. Perform overspeed inspection as follows:

**NOTE**

COMPONENTS REMOVED FROM HELICOPTER, FOLLOWING AN OVERSPEED, SHALL BE
EVALUATED AS AN INTERRELATED GROUP. REMOVAL RECORDS ACCOMPANYING EACH
COMPONENT SHALL CROSS REFERENCE PART AND SERIAL NUMBERS OF OTHER DRIVE
SYSTEM COMPONENTS REMOVED FOR EVALUATION.

**NOTE**

REFER TO ENGINE MANUFACTURER'S INSPECTION GUIDE FOR ENGINE OVERSPEED AND
INSPECTION REQUIREMENTS.

**1.** Main rotor hub assembly.

**1.1.** Remove main rotor hub. Remove main rotor blades. Perform an
overhaul

evaluation inspection. Make an entry in component record to show that
the

reason for removal was Overspeed.

**1.2.** Visually inspect main retention bolts and drag brace for shear
offset.

**2**. Main rotor blades.

**2.1.** Inspect main rotor blade for wrinkles and deformation.

**2.2.** Remove each rotor blade tip cap and inspect for evidence of
looseness

of inertia weight inside blade spar. If blades have visible screws
through

the leading edge abrasion strip to attach inertia weight inside spar,
inspect

for loose screws or distorted holes. Tighten loose balance weight
retention

nuts to torque specified in applicable main rotor blade TM or DMWR.

**2.3.** If no discrepancies are found in inspections outlined in
subparagraphs

**2.1** and **2.2**., above, the main rotor can be returned to service.

**2.4** If discrepancies are found in subparagraphs **2.1** and/or
**2.2** above,

return both blades to an authorized blade repair station. Make an entry
in

component record to show that the reason for removal was Overspeed.
Indicate

RPM and duration if known.

**3**. Tail rotor hub and blades.

**3.1.** Remove tail rotor hub and blade assembly.

**3.2.** Remove tail rotor blades.

**3.3.** Replace tail rotor blade retention bolts.

**4.** Tail rotor blades.

**4.1.** Check for bond separations anywhere on the blade. If any
separation

exists, the blade is unserviceable and not airworthy.

**4.2.** If any movement of the tip or root and balance weights has
occurred,

the blade is unserviceable and not airworthy.

**4.3.** Check the retention bushings for evidence of looseness. If any
bushing

is loose, scrap the blade.

**4.4.** If blades pass the above inspection requirements and no other

discrepancies exist, the blade can be returned to service.

**5.** Perform a close inspection of the following components. If no
visual damage

is found, the component may be returned to service.

**a.** Main transmission.

**b.** Intermediate gearbox.

**c.** Tail rotor gearbox.

**d.** Main rotor mast.

**e.** Main input drive shaft.

**f.** Tail rotor drive shaft hangers.

**g.** Stabilizer bar.

**h.** Swashplate.

**i.** Scissors and sleeve.

**j.** Tail rotor hub.

**k.** Tail rotor drive shaft (204-040-620-11).

**NOTE**

REMOVE AND CONDEMN ONLY THE 204-040-620-3 OR -7 LONG TAIL ROTOR DRIVE
SHAFTS.

**6.** Install a serviceable main rotor hub and blade assembly. Install
serviceable

tail rotor blades. Balance and install tail rotor hub and blade
assembly.

**8-4. OVERTORQUE (AIRFRAME/ENGINE)** - Overtorque is defined as any
incident in which torsional loads are introduced into the helicopter
dynamic system in excess of

established limits.

**NOTE**

COMPONENTS REMOVED FROM HELICOPTER, FOLLOWING ANY OVERTORQUE, SHALL BE
EVALUATED AS AN INTERRELATED GROUP. REMOVAL RECORDS ACCOMPANYING EACH
COMPONENT SHALL CROSS REFERENCE PART AND SERIAL NUMBERS OF OTHER DRIVE
SYSTEM COMPONENT REMOVED FOR EVALUATION AND SHALL REFLECT OVERTORQUE AS
REASON FOR REMOVAL.

**1.** When overtorque has not exceeded 56 PSI perform thorough visual
inspection of the

following components. If inspection does not reveal any discrepancies or
obvious damage to components, they may be retained in service.

**a.** Main rotor blades.

**b**. Tail rotor blades.

**c.** Main rotor hub.

**d.** Tail rotor hub.

**e.** Intermediate gearbox.

**f.** Tail rotor gearbox.

**g**. Tail rotor drive shafts.

**h.** Tail rotor drive shaft hangers.

**i.** Stabilizer bar assembly.

**j.** Swashplate.

**k**. Scissors and sleeve assembly.

**l.** Main drive shaft (BHT) as per TM.

**m.** KAFLEX drive shaft, visually inspect for the following
conditions:

**(1)** Bolt contact with adjacent plate(s).

**(2)** Plate contact with end fitting(s).

**(3)** Interconnect contact with end fitting(s).

**(4)** Contact of fail-safe surface(s).

**NOTE**

IF DISCREPANCIES ARE FOUND IN **1. m.,** **(1)** THROUGH **(4)** ABOVE,
REPLACE SHAFT.

**n.** Mast.

**o.** Transmission.

**2.** When overtorque exceeds 56 PSI but does not exceed 61 PSI:

**2.1.** Perform thorough visual inspection of components listed in

Paragraph **1. ,**subparagraphs **a.** through **m.,** above.

**2.2.** Inspect main transmission chip detector.

**2.3.** Inspect main transmission internal filter and pump inlet
screen.

**2.4.** If metal particles indicating internal failure are found,
remove the

transmission for overhaul evaluation. Make entry in component record
that

reason for removal was overtorque. Remove all transmission system oil
lines

and oil cooler. Replace external oil filter element. Flush and reinstall

lines. Install new oil cooler. Tag old cooler, "metal particle

contaminated", and return to overhaul facility.

**2.5.** If chip detector, internal filter and pump inlet screen appear
normal,

and there is no evidence of internal failure, operate the transmission
for

five hours, then check chip detector, internal filter and pump inlet
screen.

If chip detector, filter and screen inspection does not reveal
particles, the

transmission is satisfactory for service. If metal particles are found
or

if there is an evidence of internal failure, remove the transmission for

overhaul evaluation. Clean oil lines, replace oil cooler, replace
external

oil filter element and make record entries as prescribed in preceding

subparagraph **2.4.**

**2.6.** Replace main rotor hub pillow block bolts.

**2.7.** Replace main rotor trunnion cap bolts (540 M/R).

**2.8.** Remove fifth mount bolts, remove fifth mount. Perform a
thorough

inspection of bolts and fifth mount support. Check for bent bolts and
bent

fifth mount support. Check for proper bolt hole alignment between

transmission and fifth mount support. Install fifth mount.

**3.** When overtorque has exceeded 61 PSI:

**3.1.** Remove and condemn 204-040-620-3 or -7 long tail rotor drive
shaft.

**3.2.** Return following components to an overhaul facility for
overhaul

evaluation:

**a.** transmission,

**b.** main drive shaft (BHT and KAFLEX),

**c.** main rotor hub, and

**d.** mast.

**3.3.** Perform thorough visual inspection of components listed in
Paragraph **1.,**

of Heading **8-4.,** page 39.

**3.4.** Remove fifth mount bolts, remove fifth mount. Perform a
thorough

inspection of bolts and fifth mount support. Check for bent bolts and

bent fifth mount support. Check for proper bolt hole alignment between

transmission and fifth mount support. Install fifth mount.

5.  Install serviceable components.

**[T53L13B/703 ENGINES - OVERTORQUE LIMITS]{.underline}**

OUTPUT SHAFT TORQUE SHALL NOT EXCEED THE FOLLOWING VALUES:

MILITARY (30 MINUTES) - 64 PSI (114%)

NORMAL (CONTINUOUS) - 60 PSI (107%)

**[T53L11 SERIES ENGINES - OVERTORQUE LIMITS]{.underline}**

OUTPUT SHAFT TORQUE SHALL NOT EXCEED THE FOLLOWING VALUES:

TAKEOFF (5 MINUTES) - 50 PSI (926 foot pounds)

MILITARY (30 MINUTES) - 48 PSI (888 foot pounds)

NORMAL (CONTINUOUS) - 46 PSI (850 foot pounds)

**4.** When an **ENGINE** has been subjected to an overtorque condition
exceeding

the preceding limits, perform the following:

**4.1.** Check chip detector for metal chips.

**4.2.** Check oil filter for metal chips or other foreign matter.

**4.3.** If slight accumulation of foreign matter is observed, clean
chip

detector and oil filter; operate engine for 10 minutes; then repeat

subparagraphs **4.1.** and **4.2**., above.

**4.4.** If excessive accumulation of metal or foreign matter is
observed,

accomplish the following:

**a.** Perform an oil contamination inspection.

(Ref. 72-00-00, ENGINE - TROUBLESHOOTING, Para. 1.C.)

**b.** Inspect output reduction carrier and gear assembly.

**4.5.** Repeat subparagraph **4.3.,** above, increasing engine
operating time to 30

minutes.

**4.6.** Perform flight test and repeat subparagraphs **4.1** and
**4.2** above. If no

excessive accumulation of metal or foreign matter is noted, engine may
be

released for normal operation.

**8-5. LIGHTNING STRIKES** - When the helicopter is suspected of
receiving a lightning strike, the following inspections shall be
performed.

**NOTE**

COMPONENTS REMOVED FROM A HELICOPTER, FOLLOWING A LIGHTNING STRIKE,
SHALL BE EVALUATED AS AN INTERRELATED GROUP. REMOVAL RECORDS
ACCOMPANYING EACH COMPONENT SHALL CROSS REFERENCE PART AND SERIAL
NUMBERS OF OTHER DRIVE SYSTEM COMPONENTS REMOVED FOR EVALUATION.

**1.** Visually inspect all external surfaces of the helicopter with
particular attention to main rotor blades and the hub, the transmission
and mast assembly, tail rotor blades and hub, tail rotor gearbox, and
vertical fin. Check electrical instruments and systems. Replace
defective and/or damaged parts.

**2.** If visual indications of damage are present, proceed as follows:

**2.1.** Inspect main rotor blades. If blades show any sign of burns
(burn

marks can be very minute) or de-bond in any bonded areas, scrap blades.

**2.2.** Inspect main rotor hub for indication of arcing or burning.
Remove

main rotor hub and return to overhaul facility. State lightning strike

as reason for removal.

**2.3.** Remove transmission and mast assembly and return to overhaul
facility.

State lightning strike as the reason for removal.

**2.4.** Inspect tail rotor blades and hub, scrap blades if indications
of

burns or de-bonding are found. Remove tail rotor hub and return to

overhaul facility. State lightning strike as the reason for removal.

**2.5.** Remove gearboxes and return to overhaul facility. State
lightning

strike as the reason for removal.

**2.6.** Inspect vertical fin for indication of electrical arcing burns
around

mounting point of intermediate and tail rotor gearboxes.

**3.** If no visual indications or damage is found, remove main rotor
hub grips and:

**3.1.** Visually inspect bearings for signs of electrical arcing or
burning.

**3.2.** Check bearing for smooth rotation.

**3.3.** If indications of electrical arcing or burning are present or
rough

bearings, overhaul main rotor hub.

**NOTE**

IF NO INDICATIONS ARE FOUND, REASSEMBLE MAIN ROTOR HUB.

**3.2.** Remove main rotor mast assembly and visually inspect balls in
the upper

mast bearing for signs of electrical arcing or burning. Rotate bearing

during inspection so that all the surface of each ball may be observed.

Check bearing for smooth rotation. Visually inspect the lower bearing
race

on the mast, and driving spline on the mast for signs of electrical
arcing or

burning.

**a.** If indications of electrical arcing or burning are present,
remove

transmission and mast assembly and return to overhaul facility. State

lightning strike as reason for removal.

**b.** If no indications are found, reassemble transmission and mast

assembly and return to service. After five hours, remove chip

detectors and oil filter and inspect for chips. If no indications are

found, return transmission to service. If indications are found,

remove transmission and mast assembly and return to overhaul facility.

State lightning strike as the reason for removal.

**3.3.** Remove output quill assembly from tail rotor gearbox. Visually
inspect

gear teeth for signs of electrical arcing or burning. Rotate tail rotor
mast

to check for smooth rotation of bearings.

**a.** If evidence of electrical arcing or burning is found or if
bearings

do not rotate smoothly, remove gearbox and return to overhaul

facility. State lightning strike as the reason for removal.

**b.** If no indications of damage are found, and if bearings rotate

smoothly, reassemble tail rotor gearbox and return to limited service

as defined below:

**(1)** After five hours, remove chip detector and inspect for chips.

**(2)** If no indications are found, return tail rotor gearbox to

service.

**(3)** If indications are found, return tail rotor gearbox to

overhaul facility. State lightning strike as the reason for

removal.

**(4)** Remove output quill assembly from intermediate gearbox.

Visually inspect gear teeth for signs of electrical arcing or

burning. Rotate quills to check for smooth rotation of bearings.

**(a)** If evidence of arcing or burning is found or if

bearings do not rotate smoothly, remove intermediate gearbox

and return to overhaul facility. State lightning strike as

the reason for removal.

**(b)** If no indications of damage are found, and if

bearings rotate smoothly, reassemble intermediate gearbox and

return to limited service as defined below:

**1.** After five hours, remove chip detector and inspect

for chips.

**2.** If no indications are found, return intermediate

gearbox to service.

**3.** If indications are found, return intermediate gearbox

to overhaul facility. State lightning strike as the reason

for removal.

**8-6. MAST BUMPING**

**1.** Visually inspect the mast area where the static stop would
contact the mast. If no surface deformation of the mast has occurred,
the inspection is complete.

**2.** If there is visual evidence of surface deformation of the mast
due to

static stop contact, perform the following:

**2.1.** Evaluate the condition of the mast per the damage limits.
(Refer to

applicable TM.)

**2.2.** Inspect and replace the following items if damage is found:

**a.** Main rotor hub trunnion cap or pillow block attach bolts and drag

brace jam nuts and attach bolts for security.

**b.** Flight control system for bent or damaged tubes and rod end

bearings.

**c.** Structure at transmission mounting points.

**d.** Lift link and structure for damage, security and distortion.

**e.** Transmission sump oil filter, external oil filter, and chip

detector for metal particles.

**f.** Main drive shaft.

**g.** Tail rotor drive shafts and hanger assemblies for obvious damage.

**h.** Main transmission output tail rotor drive quill.

**i.** Top forward section of fuselage.

**8-7. AFTER WIRE STRIKE**

**1.** Lower Wire Strike Protection System (WSPS) Assembly.

**1.1.** Inspect for obvious damage to WSPS.

**1.2.** Inspect attachment area for damage.

**2.** Windshield Deflector and Upper WSPS Assembly.

**2.1.** Inspect for obvious damage to WSPS.

**2.2.** Inspect attachment area for damage.

**3.** Windshield Wiper Deflector (WWD).

**3.1.** Inspect for obvious damage to WWD.

**3.2.** Inspect attachment area for damage.

**8-8. AFTER LOWER WSPS GROUND CONTACT**

**1.** Inspect for obvious damage.

**2.** Inspect attachment area for damage.

**3.** Remove panel and inspect structure and directional control tubes
and

bellcranks for damage.

**4.** Replace breakaway tip assembly.

**NOTE**

LOSS OF BREAKAWAY TIP OR DAMAGE NOT AFFECTING STRUCTURAL INTEGRITY OF
INSTALLATION ARE NOT CAUSES FOR GROUNDING OF AIRCRAFT. HOWEVER,
REPLACEMENT OF TIP AND DAMAGE REPAIR SHALL BE ACCOMPLISHED AS SOON AS
PRACTICAL.

**8-9. AFTER AIRCRAFT IS FLOWN INTO AREA WITH BLOWING SAND AND/OR LOOSE
GRASS ENVIRONMENT.**

**NOTE**

IF FOD SCREEN AND SAND AND DUST SEPARATOR ARE INSTALLED, REMOVE UPPER
HALVES TO ACCOMPLISH THIS INSPECTION. IF BLOCKAGE IS EVIDENT, THE LOWER
HALF OF THE SEPARATOR MUST BE REMOVED TO ENSURE COMPLETE REMOVAL OF
GRASS OR FOREIGN MATERIAL.

**NOTE**

IF THE IMPROVED PARTICLE SEPARATOR (IPS) IS INSTALLED, REMOVE ANY
FOREIGN OBJECTS FROM THE SCREEN OR SIDE OF VORTEX TUBE PANELS. BLOWING
SAND CAN PENETRATE THROUGH VORTEX TUBES AND IF ENGINE IS NOT RUNNING,
WILL NOT BE SCAVENGED OVERBOARD. IN THESE CIRCUMSTANCES SAND CAN SETTLE
IN BOTTOM PLENUM OF IPS. THE TOP OF IPS SHOULD BE REMOVED AND ALL SAND
REMOVED FROM IPS BOTTOM HALF.

**8-10. AFTER WASHING HELICOPTER.**

**1.** Remove left and right pylon access doors. Using a clean cloth,
wipe water deposits from pylon structural members. Reaching aft onto
forward engine deck through rear pylon structures, wipe water from
engine deck.

**2.** Check pitot static system for moisture (drain plug removed).

**3.** Purge lubricate tail rotor grip assemblies.

**8-11. AFTER HELICOPTER HAS BEEN SUBJECTED TO SALT WATER OR SALT WATER
SPRAY.**

**1.** Wash entire helicopter with fresh water, particularly inside of
engine

compartment doors. Wash all compartments which were exposed to salt
water.

Make a detail check of all surfaces for corrosion. Apply corrosion
preventive

compound to exposed non painted, anodized, or cadmium plated assemblies.

Clean engine compressor in accordance with applicable engine TM.

**8-12. HELICOPTERS OPERATED IN SALT LADEN ENVIRONMENT:**

**1.** Using a mild soap detergent, wash blades daily. Rinse with clear
water

and dry. All aircraft down for maintenance or non-flyable storage are
not

subject to blade wash inspection.

**8-13. AFTER HELICOPTER HAS BEEN PARKED OR OPERATED IN RAIN, ICE, OR
SNOW.**

**1.** Purge lubricate tail rotor hub and blade grip bearings.

**2.** Open engine inlet area and remove upper air filter assembly.
Inspect

and clean particle separator parts.

**NOTE**

INSPECTION DOES NOT APPLY TO HELICOPTERS WITH SELF-PURGE TYPE
SEPARATORS.

**NOTE**

INSPECTION NOT REQUIRED IF HELICOPTER WAS PARKED WITH PROTECTIVE COVERS
INSTALLED.

**8-14. AFTER OVERFLOW OF BATTERY AND/OR BATTERY SUMP JAR** (IF SUMP JAR
IS INSTALLED).

**1.** Inspect sheet metal surfaces and overlaps, both internal and
external, for damage.

**2.** Inspect rivets, bolts, screws, and other hardware in area,
internally and externally for damage.

**3.** Inspect hidden areas in vicinity of battery and sump jar for
damage.

**4.** Inspect all metal parts throughout contaminated area for damage.

**8-15. TRANSMISSION OIL OVER TEMPERATURE.**

**1.** Troubleshoot transmission system to determine cause.

**2.** Replace transmission, mast, oil cooler and external oil filter if
cause is due to transmission internal failure.

**3.** If cause is due to oil system external to transmission and oil
temperature did not exceed 130 degrees C (266 degrees F) for 15 minutes,
drain and refill transmission oil system.

**4.** If temperature exceeded above limits, replace transmission and
mast. If abnormal contamination is present, also replace oil cooler and
external filter.

**8-16. COMPLETE LOSS OF TRANSMISSION OIL.**

**1.** Troubleshoot transmission oil system to determine cause.

**2.** If engine power was applied after complete loss of oil, replace
transmission and mast. If abnormal contamination is present, also
replace oil cooler and external oil filter

**3.** Inspect quick disconnects for engagement and wear.

**CHAPTER 9**

**CONDITIONAL INSPECTIONS (ENGINE)**

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Conditional Inspections (Engine) found in **Chapter 9** of the IPG are
inspections

required as a result of an unusual event such as engine oil filter
bypass or engine over temperature.

**NOTE**

THERE ARE NO PRESCRIBED INTERVALS FOR CONDITIONAL INSPECTIONS.

**9-1.** **INSPECT FOR FOREIGN OBJECT DAMAGE (FOD).**

**1.** Open inlet guide vanes manually and conduct a visual inspection
of the inlet housing (inlet guide vane and first stage compressor rotor
through the inlet ducts).

**2.** If damage exceeds limits or appears to extend beyond the first
stage compressor rotor, remove the upper compressor housing half and
inspect compressor

blades, vanes, centrifugal impellers, and compressor housings.

(Ref. 72-30-XX, of appropriate maintenance manuals).

If centrifugal compressor impeller is damaged beyond limits, return
engine to

Overhaul.

**3.** Inspect all visible air diffuser vanes for nicks, dents, and
burrs.

Minor nicks, dents and burrs are acceptable provided that mutilation has
not occurred as

defined by the appropriate manual.

**9-2. SUSPECTED COMPRESSOR STALL OR SURGE.**

Engine compressor stall or surge is characterized by a sharp rumble or a
series of

load sharp reports, severe engine vibration and a rapid rise in exhaust
gas

temperature (EGT), depending on severity of surge. When a surge has been
reported,

progressively perform **9-2. SUSPECTED COMPRESSOR STALL OR
SURGE.,**Paragraphs **1., 2.,** and **3.** below**,** as indicated by
discrepant conditions.

**NOTE**

STALL INSPECTION IS NOT REQUIRED FOR NOISE CAUSED BY BLEED BAND CYCLING
OR SURGE BELOW 85 PERCENT N1 THAT IS NOT ACCOMPANIED BY A RAPID RISE IN
EGT.

**NOTE**

COMPONENTS REMOVED FROM A HELICOPTER, FOLLOWING A COMPRESSOR STALL OR
SURGE, SHALL BE EVALUATED AS AN INTERRELATED GROUP. REMOVAL RECORDS
ACCOMPANYING EACH COMPONENT SHALL CROSS REFERENCE PART AND SERIAL
NUMBERS OF OTHER DRIVE SYSTEM COMPONENTS REMOVED FOR EVALUATION.

Discuss circumstances of reported compressor stall with pilot. Determine
N1 speed at which reported stall occurred. Check helicopter and engine
log for any pertinent history.

**1.** Power plant.

**1.1.** Examine inlet screen for blockage.

**1.2.** Inspect the engine in accordance with engine manufacturer's
inspection

guide.

**1.3.** If compressor is dirty, wash in accordance with approved engine

manufacturer's method.

**2**. Power train.

If compressor stall occurs below 85 percent N1 speed, comply with the
following subparagraphs **2.1**., through **2.3**. below:

**2.1.** Remove magnetic chip detectors from transmission, intermediate

gearbox and tail rotor gearbox, and inspect for metal particles.

**2.2.** If no evidence of damage is found on tail boom vertical fin and
no

indication of metal particles are found on chip detectors; clean chip

detectors and reinstall. Return helicopter to flight status and repeat

chip detector inspection in 5 to 10 hours. If positive indication of

damage is found on tail boom pylon or metal chips are found on chip

detectors on initial 5 to 10 hour inspection, comply with subparagraphs
**2.4**

through **2.7** below.

**2.3.** Visually inspect main drive shaft. Main BHT drive shaft,
inspect for

internal and curvic coupling damage. KAFLEX drive shaft, inspect for the

following conditions:

**a.** Plate contact with end fitting(s).

**b**. Interconnect contact with end fitting(s).

**c.** Contact of fail-safe surface(s).

**NOTE**

IF ANY ONE OF THE ABOVE CONDITIONS ARE FOUND, REPLACE SHAFT.

RETURN SHAFT TO SERVICE IF NO DAMAGE IS FOUND.

If compressor stall occurs at 85 percent N1 or above, comply with the
preceding Paragraph **2**., (including subparagraphs **2.1, 2.2** and
**2.3**) and the following subparagraphs **2.4**, through **2.7**. and
Paragraph **3.**

**2.4.** Remove and condemn 204-040-620-3 and -7 long tail rotor drive
shaft.

**2.5.** Remove tail rotor gearbox from helicopter and remove input
quill. With

a 10 power glass, inspect gear teeth on pinion and gear for damage. If

no evidence of scoring or scuffing is found and there is no other damage
that

would render gearbox unserviceable, it may be reassembled and
reinstalled for

continued use. If gear teeth are scored or scuffed or there is other
damage

that would render gearbox unserviceable, replace gearbox.

**2.6.** Remove input and output drive quill from intermediate gearbox
and

inspect gear teeth on pinion and gear for damage with a 10 power glass.

If no evidence of scoring or scuffing is found and there is no

mechanical damage that would render gearbox unserviceable, reassemble

and return to service. If gear teeth are scuffed or scored or gearbox

has sustained other damage; replace gearbox.

**2.7.** Remove the tail rotor drive quill from the transmission and

inspect the gear teeth for damage with a 10 power glass. If there is no

indication of scoring or scuffing and there is no other damage that

would render the transmission unserviceable, it is suitable for

continued use. If gear teeth are scored or scuffed or there is other

damage that would render the transmission unserviceable, replace

transmission and comply with subparagraph **2.8**., below.

**2.8.** If transmission is replaced, the tail rotor hanger bearing
assemblies

and tail rotor hub and blade assembly must also be replaced and
procedures

outlined in subparagraphs **a**. through **e.** below, performed.

**NOTE**

PERFORM AN OVERHAUL EVALUATION ON TAIL ROTOR HUB AND BLADE. MAKE AN
ENTRY IN COMPONENT RECORD TO SHOW THAT THE REASON FOR REMOVAL WAS
COMPRESSOR STALL.

**a.** Remove inboard and outboard drag brace bolts. Check bolts for

deformation, and perform a magnetic particle inspection. If

satisfactory, return to service.

**b.** Visually inspect stabilizer bar outer tubes for bending.

(Allowable deflection is 0.150 inch in each tube.)

**c.** Remove main rotor pillow blocks from main rotor yoke and check

for deformation of bushing holes in pillow blocks and yoke.

Replace main rotor trunnion cap bolts (540 M/R).

**d.** Perform close visual inspection of all main rotor components.

**e.** If any discrepancies are noted as a result of inspection in

subparagraphs **a.** through **d.** above, remove and replace main rotor
hub

and blade assembly, stabilizer bar assembly, and mast assembly.

Removed assemblies shall have an overhaul evaluation performed. Make

an entry in component records to show that the reason for removal was

Compressor Stall.

**3.** Airframe.

**3.1.** Check tail boom vertical fin for evidence of damaged skin
panels

and/or structure and rivets for looseness and/or sheared heads. If

inspection shows no indications of damage, return helicopter to service.

If positive evidence of damage is found, comply with subparagraphs
**3.2**

through **3.4** below.

**3.2.** Remove skin from tail boom vertical fin adjacent to tail rotor

gearbox mounting. Inspect all support structures in this area and

repair as required. Install new skin.

**3.3.** Make close visual inspection of complete tail boom structure
for

distortion, buckles, skin cracks and sheared or loose rivets, paying

particular attention to tail boom attachment points and adjacent
fuselage to

tail boom structure and intermediate gearbox support structure.

**3.4.** Make close visual inspection of main pylon support and engine

mount attachment structure for distortion buckles, cracks, sheared or

loose rivets, etc.

**9-3. ENGINE IS DROPPED DURING HANDLING.**

**CAUTION**

**IF ENGINE IS IN SHIPPING CONTAINER, INSPECT CONTAINER AND CONTAINER
ENGINE MOUNTS**

**FOR DAMAGE. IF EXTENSIVE DAMAGE TO SHIPPING CONTAINER OR SHIPPING
CONTAINER ENGINE**

**MOUNTING SYSTEM IS FOUND, ENGINES MUST BE RETURNED TO OVERHAUL FOR
INSPECTION OF ALL**

**MAIN BEARINGS**

**1.** Check accessory drive gearbox for cracked mount flanges or loose
bolts.

**2.** Check overspeed governor and tachometer drive for cracks,
distortion,

and bent shafts.

**3.** Check oil filter for loose bolts and damaged filter elements.

**4.** Check power-driven rotary (oil) pump for loose bolts and cracked
flanges.

**5**. Check engine mounting pads for cracks.

**6.** Check all hose connections for security.

**7.** Check all accessories for loose bolts, nuts, connections, and
cracked mount

flanges.

**8**. Check inlet, compressor, and combustor housings for cracks or
loose bolts.

**9.** If no visual damage is apparent, accomplish the following
inspections:

**9.1.** Perform a complete engine ground operational test (with engine
on

aircraft) and include vibration and coastdown checks.

**NOTE**

THE MINIMUM TEST TIME IS 30 MINUTES. VIBRATION LEVELS MUST BE WITHIN
ESTABLISHED

LIMITS. IF NO DEFECTS ARE NOTED, ENGINE IS CONSIDERED SERVICEABLE. (REF.
71-00-00,

PARA. 12.E.)

**9.2.** Perform inspection of oil filter, screens, and chip detector
for chips,

lint, or other foreign material.

**NOTE**

IN THE EVENT THE SEVERITY OF DROP IS SUCH THAT ITEMS AS CALLED OUT IN
HEADING **9-3.**

**ENGINE IS DROPPED DURING HANDLING.,** PARAGRAPHS **1.** THROUGH
**8.,** ABOVE ARE DISCREPANT,

IT IS RECOMMENDED THAT ENGINE BE RETURNED TO A DESIGNATED OVERHAUL
FACILITY FOR

FURTHER CORRECTIVE ACTION.

**9-4. ENGINE SUDDEN STOPPAGE.**

**CAUTION**

**THE FOLLOWING ENGINE INSPECTION MUST BE COMPLETED IN THE EVENT OF
AIRCRAFT DRIVE**

**SYSTEM STOPPING, EVEN MOMENTARILY. SUDDEN STOPPAGE IS INTERPRETED TO
INCLUDE THE**

**SHOCK FELT BY THE DRIVE SYSTEM WHEN THE AIRCRAFT ROTOR BLADES COME IN
CONTACT WITH**

**THE GROUND, WATER, TREES, OR OTHER OBSTACLES THAT WOULD CAUSE DAMAGE
REQUIRING**

**AIRCRAFT ROTOR BLADE CHANGE.**

**IT IS ADVISED THAT ENGINES SUBJECTED TO SUDDEN STOPPAGE BE RETURNED TO
A DESIGNATED OVERHAUL FACILITY FOR THE FOLLOWING INSPECTION, AS FAILURE
TO DO SO MAY AFFECT AIRWORTHINESS. DETAILED DISASSEMBLY, INSPECTION AND
ASSEMBLY INSTRUCTIONS ARE PROVIDED IN THE OVERHAUL MANUAL, ALLIED SIGNAL
NO. 330.3.**

**1.** Inspect output reduction carrier and gear assembly (1-030-350-08
or

1-030-350-12) and sun gearshaft (1-030-192-03 or 1-030-192-04).

**1.1.** Perform a magnetic particle or fluorescent penetrant inspection
on

all parts included in the reduction gearing system.

**NOTE**

CRACKING MAY OCCUR LONGITUDINALLY ALONG GEAR TEETH. CRACKS CAN BE
CONSIDERED

PARTIAL SEPARATION OF METAL RESULTING FROM UNDUE STRESSES. CHIPPING AND
FLAKING

REPRESENT VARIOUS FORMS OF CRACKING.

**1.2.** Perform **8-4 Overtorque (Airframe/Engine) Inspection,** of the
IPG.

**1.3.** If there is no damage found in the preceding inspections,
perform

**9-9 Engine Oil Contamination Inspection**, of the IPG.

**1.4.** If damage is found in the preceding inspection, perform
overspeed

inspection found in **9-5 Engine Overspeed Inspection, Chapter 9,** of
the IPG**.**

**2.** If damage is found during **9-5 Engine Overspeed Inspection,**
perform **9-9 Engine**

**Oil Contamination Inspection**, of the IPG.

**9-5. ENGINE OVERSPEED.**

If engine has been subjected to an overspeed condition, proceed as
follows:

**1.** Remove and check oil filter for metal chips or other foreign
matter.

**2**. Remove and check chip detector for metal chips.

**NOTE**

IF CHIPS ARE FOUND IN OIL FILTER OR CHIP DETECTOR, PERFORM AN OIL
CONTAMINATION

INSPECTION. (REF. 72-00-00, ENGINE - TROUBLESHOOTING, PARA. 1.C).

**3.** If gas producer (N1) overspeed limits are exceeded, proceed as
follows:

**3.1.** Perform an INTERNAL (HOT END) INSPECTION. (REF. 72-00-00,
ENGINE -

TROUBLESHOOTING, PARA. 1.D)

**3.2.** Check compressor rotor assembly by mechanically rotating and
listening

for indications of rubbing.

**4.** If output shaft (N2) overspeed limits are exceeded, proceed as
follows:

**[T53L11 OVERSPEED LIMITS]{.underline}**

101 PERCENT AT TAKE-OFF POWER.

101 PERCENT AT MAXIMUM CONTINUOUS POWER.

**[T53L13B OVERSPEED LIMITS]{.underline}**

1\. AN N2 OVERSPEED CONDITION EXISTS UNDER THE FOLLOWING CONDITIONS:

WHEN N2 SPEED EXCEEDS 101 PERCENT (21,300 POWER TURBINE RPM, OUTPUT
SHAFT

6637 RPM) AT THE TAKEOFF POWER POSITION.

2\. THE FOLLOWING MAXIMUM STEADY-STATE N2 SPEEDS MAY BE ATTAINED,
PROVIDING THE

MAXIMUM CORRESPONDING TORQUE PRESSURE IS NOT EXCEEDED WITHOUT CREATING
AN OVERSPEED

CONDITION:

**[STEADY STATE COMBINATIONS]{.underline}**

**[N2 SPEED - MAX]{.underline}** **[TORQUE PRESSURE - MAX]{.underline}**

107% (7,032 RPM) 10 PSI

106% (6,966 RPM) 21 PSI

105% (6,900 RPM) 32 PSI

103% (6,769 RPM) 42 PSI

102% (6,703 RPM) 53 PSI

101% (6,637 RPM) 60 PSI

**[T53L703 OVERSPEED LIMITS]{.underline}**

109% (7,163 RPM) AT TAKE-OFF POWER.

**4.1.** Visually inspect power turbine rotor assembly for damaged or
missing

blades (view through tailpipe).

**4.2.** Perform tip clearance inspection on second stage power turbine
blades

through exhaust diffuser (0.025 inch minimum.)

**NOTE**

IF DISCREPANCIES ARE NOTED, PERFORM AN INTERNAL (HOT END INSPECTION).
(REF. 72-00-00, ENGINE - TROUBLESHOOTING, PARA. 1.D.)

**4.3.** Determine and correct cause of overspeed.

**4.4.** Perform engine operation check. If no discrepancies are noted,

the engine is serviceable.

**9-6. ENGINE OIL OVERTEMPERATURE.**

An engine overtemperature condition exists when limits given are
exceeded.

**1.** Observe the following limits for normal operating conditions:

**1.1.** The maximum (red line) OIL-IN temperature is 99 degrees C

(210 degrees F). When oil temperature exceeds 99 degrees C (210 degrees
F)

refer to Paragraphs/subparagraphs below as appropriate.

**1.2.** A steady-state engine OIL-IN temperature of 100 degrees C

(212 degrees F) is acceptable provided the oil filter is inspected every

50 hours of engine operation for excessive accumulation of carbon or
metal

particles.

Under abnormal (emergency) conditions, such as an oil cooling system
malfunction or

failure, the following procedures and engine oil temperature limits will
minimize

the risk involved in operating an engine which has exceeded temperature
limits.

**CAUTION**

**IT MUST BE CLEARLY UNDERSTOOD THERE IS A POSSIBILITY THAT MECHANICAL
COMPONENTS MAY**

**SUFFER DAMAGE IF ENGINE OPERATING CONDITIONS ARE EXTENDED BEYOND THESE
LIMITS.**

**2.** At oil temperatures from 99 degrees C (210 degrees F) to 130
degrees C

(266 degrees F) for 10 minutes or less, check engine oil screens and
main oil

filter.

**3.** At temperature from 99 degrees C (210 degrees F) to 130 degrees C

(266 degrees F) for more than 10 minutes, but no more than 30 minutes,
proceed

as follows:

**3.1.** Change oil, clean all screens and main oil filter. Ground run

engine for 30 minutes and recheck main oil filter for carbon and metal

particles. If contamination is found, clean oil screens and oil filter.

Repeat oil change and ground run engine.

**4.** At temperatures from 99 degrees C (210 degrees F) to 130 degrees
C

(266 degrees F) for greater than 30 minutes, perform following oil
overtemperature

inspection, Paragraph **7**., below.

**5.** When oil temperature reaches 131 degrees C (268 degrees F) and
above for any

length of time, perform following oil overtemperature inspection,
Paragraph **7.,**

below.

**6.** When oil temperature reaches 150 degrees C (302 degrees F), the
engine must

be returned to Overhaul.

**7.** Perform following oil overtemperature inspection as required:

**7.1.** Remove combustor turbine assembly. (Ref. 72-40-00)

**7.2.** Disassemble combustor turbine assembly to permit removal of
power

turbine rotor and bearing housing assembly.

**7.3.** Disassemble power turbine rotor and bearing housing assembly to
permit

removal of No. 3 and 4 position main bearings. Determine part numbers of

bearings and:

**a.** Replace bearing 1-300-176-04, 1-300-584-02, and 1-300-015-02/04.

**b.** Inspect other bearings for coke/general condition. Replace if
necessary

**c.** Inspect No. 2 main bearing seals for coke/general condition.

Replace if necessary.

**7.4.** Disassemble gas producer system components to permit removal of
No. 2

position main bearing and No. 2 main bearing seals. Determine part
numbers

of bearings and:

**a.** Replace bearing 1-300-584-02, 1-300-176-04.

**b.** Inspect other No. 2 bearing part numbers for coke and condition.

Replace if necessary.

**c.** Reassemble gas producer system components, power turbine rotor

and bearing housing assembly, and combustor turbine assembly.

Reinstall combustor turbine assembly.

**7.5** Remove accessory drive gearbox.

**a.** Disassemble gearbox to permit removal of bearings 1-300-002-01/02

and 1-300-0001/02 from pinion gearshaft and bearing assembly, bearings

1-300-0001/02 from thrust bearing liner assembly and bearings

1-300-12-01/02 from starter generator drive gearshaft assembly.

(Ref. 72-60-01) Determine part number of bearing and:

**b.** Replace bearing 1-300-002-01/02, and 1-300-012-01.

**c.** Inspect bearing 1-300-012-02 and all remaining installed bearings

for coking and heat discoloration. Replace if necessary.

**d.** Inspect all gears and splined parts for coking and heat

discoloration. Replace if necessary.

**e.** Remove output reduction carrier and gear assembly.

**f.** Inspect accessible gears and splined parts for signs of heat

distortion. Replace any part that is discolored.

**9-7. ENGINE SUBJECTED TO EXCESSIVE G-LOADS (HARD LANDING, SEVERE
MANEUVERS).**

If it is suspected that excessive G loads have been imposed on engine,
conduct the

following inspections immediately after flight during which the
excessive loads occurred:

**1.** Inspect accessory drive gearbox for cracked mount flanges or
loose bolts.

**2.** Inspect overspeed governor and tachometer drive for cracks,
distortion and

bent shaft.

**3.** Inspect oil filter for loose bolts and damaged filter elements.

**4.** Inspect oil pump for loose bolts and cracked flanges.

**5.** Inspect fuel control assembly for cracked flanges and loose nuts.

**6.** Inspect engine and aircraft mounts for cracks, loose bolts,
bending, or distortion in any of the following areas:

**a.** Engine mounts.

**b.** Accessory drive gearbox mount flanges.

**c.** Accessory mount flanges.

**d.** Inlet, compressor, or combustor housings..

**NOTE**

IF THE AIRCRAFT-FURNISHED ENGINE MOUNT LEGS EXHIBIT ANY CRACKS, BENDING,
OR

DISTORTION, IT IS RECOMMENDED THAT THE ENGINE BE RETURNED TO OVERHAUL AS
EXTREMELY

HIGH G-LOADS HAVE BEEN IMPOSED. IT IS FURTHER RECOMMENDED THAT ALLIED
SIGNAL BE

CONTACTED TO PROVIDE ADDITIONAL DIRECTION.

**7.** Inspect air, oil, and fuel hose connections for tightness.

**8.** Inspect all accessories for loose bolts, nuts, and connections.

8.  **ENGINE INLET BLOCKAGE.**

**NOTE**

ANY TIME THE AIRCRAFT IS FLOWN IN A LOOSE GRASS/FOLIAGE ENVIRONMENT, OR
IF IT IS

SUSPECTED THAT RAGS, PAPER OR OTHER DEBRIS COULD HAVE BEEN INGESTED, THE
ENGINE

SHALL BE INSPECTED FOR BLOCKAGE AROUND THE INLET GUIDE VANES. FAILURE TO
PERFORM

THIS INSPECTION COULD RESULT IN LOSS OF POWER.

**1.** Inlet blockage inspection.

**1.1.** Remove the particle separator (both halves) and aircraft inlet
screen

(if installed), and inspect the engine inlet area.

**1.2.** Inspect the inlet housing struts and each inlet guide vane for
rags,

paper, grass, foliage or other foreign material blockage or partial
blockage.

**1.3.** Completely remove any foreign material that may be lodged on
the inlet

strut or guide vanes. Special attention should be given to the lower

(4 through 8 o'clock) portion of the vane assembly.

**1.4.** If blockage or partial blockage is evident or suspected, remove
and

scrap all the first and second stage blades and replace with new blades.

**1.5.** If removed, reinstall particle separator and aircraft inlet
screen.

**1.6.** Perform standard engine vibration check with the engine
installed in the

aircraft. (Ref. 71-00-00, Para 12.E.)

**9-9. ENGINE OIL CONTAMINATION.**

Whenever an oil contamination inspection has revealed a continuance or
an increase

of chips in the oil filter or on the chip detector, but output reduction
carrier and

gear assembly has freedom of movement and emits no unusual noises,
proceed as

follows:

***WARNING***

***PROLONGED CONTACT WITH LUBRICATING OIL MAY CAUSE A SKIN RASH. THOSE
AREAS OF SKIN***

***AND CLOTHING THAT MAY COME IN CONTACT WITH LUBRICATING OIL SHOULD BE
THOROUGHLY***

***WASHED IMMEDIATELY. SATURATED CLOTHING SHOULD BE REMOVED IMMEDIATELY.
AREAS IN***

***WHICH LUBRICATING OIL IS USED SHOULD BE ADEQUATELY VENTILATED TO KEEP
MIST AND FUMES***

***TO A MINIMUM.***

**CAUTION**

**LUBRICATING OIL MAY SOFTEN PAINT UPON CONTACT. IF LUBRICATING OIL IS
SPILLED ON**

**PAINTED SURFACES, THESE SURFACES SHOULD BE THOROUGHLY WASHED.**

**1.** Check main oil filter elements for chip accumulation which could
have placed

the filter into bypass. Clean with dry cleaning solvent (Ref. 72-00-00,
62,

Table 203, or appropriate manual) and reinstall.

**2.** Remove and inspect No. 2 bearing strainer and No. 3 and 4 bearing
strainer

bore for metal chips. If chips are present, remove and inspect three

reduction gear oil transfer tube strainers (Ref. 72-10-01) and overspeed

governor and tachometer drive oil throttle strainer (Ref. 72-60-02).
Forward

engine to Overhaul if metal chips have clogged more than one-third of
flow

area of any one of previously mentioned strainers. If amount of chips is
not

excessive, clean and reinstall strainers and proceed to Paragraph **3.**
below.

**3.** Presence of chips in previously mentioned strainers indicates
that bypass of

oil filter has occurred. Replace oil filter.

**4.** Drain all oil from accessory gearbox, aircraft, oil tank, and oil
cooler.

**5.** Remove metal chips from chip detector. Clean with dry cleaning
solvent (Ref.

72-00-00, 62, Table 203).

**6.** Check No. 2 bearing scavenge line for metal contamination. If
chips are

evident, disassemble gas producer as necessary, inspect all oil wetted

components; replace parts as needed. Flush components with dry cleaning

solvent (Ref. 72-00-00, 62, Table 203) and reinstall.

**7.** Check No. 3 and 4 bearings scavenge line for metal contamination.
If chips

are evident, remove combustor turbine assembly, disassemble power
turbine and

bearing housing assembly, and inspect bearings and other oil wetted
components.

Replace if required (Ref. 72-50-04). Flush components with dry cleaning
solvent

(Ref. 72-00-00, 62, Table 203) and reinstall.

**8.** If chips are suspected to come from reduction gearing, remove
reduction

gearing, inspect its condition and replace if required.

**9.** Remove accessory drive gearbox (Ref. 72-60-01). Remove and
inspect shaft

gear assembly. Particularly note condition of upper and lower bearings
on this

shaft. Inspect and clean scavenge strainer. Flush shaft gear assembly
and

internal components of gearbox with dry cleaning solvent (Ref. 72-00-00,
62.

Table 203) and reassemble.

**10.** Flush aircraft oil system and replace oil cooler on aircraft not
equipped

with auxiliary external oil filter.

**11.** Service oil system with lubricating oil (Ref. 41 or 42, Table
203) Operate

engine at 70 to 80 percent N1 for 5 minutes. Shut down engine and allow
to cool.

**CAUTION**

**ANY MALFUNCTION IN OIL PRESSURE IN EXCESS OF PLUS OR MINUS 5 PSI, OR
RAPID RISE IN**

**OIL TEMPERATURE AT ANY PRESET POWER SETTING, IS CAUSE FOR IMMEDIATE
ENGINE SHUTDOWN.**

**12.** Check oil filter elements, chip detector, and strainers.

**13.** Inspect chip detector and oil filter strainers for chips. Amount
of chips

noted should be less than original amount. If so, repeat preceding
Paragraphs

**10.** and **11.**, increasing engine operating time to 10 minutes.

**NOTE**

CHIPS IN OIL FILTER MAY ORIGINATE IN OIL SUPPLY TANK; CHIPS ON CHIP
DETECTOR

ORIGINATE IN ENGINE.

**14.** Repeat inspection, servicing and operating cycle, increasing
engine

operating time to 30 minutes. If no appreciable amount of chips or other

contaminates is noted, engine may be returned to service. If amount of
chips or

other contaminants remains the same or increases, perform oil sample
analysis (Ref.

72-00-00, ENGINE - INSPECTION, Para. 1.G.); forward engine to Overhaul.

**NOTE**

THE FOLLOWING ACTIONS ARE RECOMMENDED TO ENSURE THAT OIL, CHIPS, OR
OTHER

CONTAMINANT SAMPLES ARE AVAILABLE TO AID IN THE DIAGNOSIS OF THE
PROBLEM. IF AN

ALLIED SIGNAL REPRESENTATIVE IS CALLED IN, RETAIN THE SAMPLE FOR HIS
EVALUATION AND

ACTION.

**a.** Exercise care to prevent additional contamination of sample.

**b.** Mark oil, chips, or contaminant sample to include operator's
name,

address, location on the engine from which the sample was taken, engine

model and seal number, time since new, time since overhaul, and last

related maintenance action. Include the oil vendor's name, batch

number, and date of manufacture on the sample.

**c.** If the engine is being returned for repair or overhaul, return
marked

sample in engine container.

**15.** If the amount of carbon particles found on the engine oil filter
elements

covers 15 percent or more of the surface area, proceed as follows:

**15.1.** Clean and reinstall oil filter assembly.

**15.2.** Drain all oil from accessory drive gearbox, oil tank, and oil
cooler.

**15.3.** Remove and inspect No. 2 strainer, and No. 3 and 4 bearing
strainers.

If carbon particles are present, oil filter has bypassed. Remove, clean,
and

reinstall reduction gear oil transfer tube strainers and overspeed
governor

and tachometer drive oil throttle strainer. Clean and reinstall No. 2
bearing

strainer and No. 3 and 4 bearing strainers.

**15.4.** Refill oil tank to capacity with new oil.

**15.5.** Start engine and run at 70 to 80 percent N1 for 15 minutes.

**15.6.** Shut down engine; then remove, inspect, and clean oil filter
and

strainers. Reinstall oil filter and strainers.

**15.7.** If contamination is excessive, repeat procedure until filter
is clean

after engine run.

**9-10. LOSS OF POWER OR HIGH EXHAUST GAS TEMPERATURE CONDITION.**

Thoroughly investigate the engine inline (engine de-ice) valve for
proper functioning prior to proceeding with troubleshooting procedures.
(Refer to applicable engine manual).

**9-11. ENGINE OVERTEMPERATURE.**

Perform an engine over-temperature inspection. (Refer to applicable
engine TM.)

**NOTE**

IF ENGINE CANNOT BE OPERATED WITHOUT EXCEEDING EGT LIMITS AS SPECIFIED
IN TM, IT IS AN INDICATION OF ENGINE MALFUNCTION OR INSTRUMENT ERROR.
REFER TO TROUBLESHOOTING TO DETERMINE CAUSE AND CORRECT ACTION, AS
OVER-TEMPERATURE INSPECTION MAY NOT BE REQUIRED.

**APPENDIX**

**\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_**

Letter from Bell Textron

Ref: Overhaul and Retirement Schedule, Manuals, and Technical
assistance.

***B**e**ll Helicopter*** Post Office Box 482

A Textron Company Fort Worth, Texas 76101

Dear Bell Helicopter Excess/Surplus Aircraft Operators:

Bell Helicopter is aware of several situations in which many operators
need technical assistance in maintaining their UH-1 Helicopters. When
the helicopters are surplused by the Defense Logistics Agency (DLA),
many operators do not receive the appropriate Technical Manuals to
maintain their helicopters.

The military Technical Manuals (TM\'s) required to maintain the UH-1
are:

TM 55-1520-210-23P-1/-2/-3 PARTS MANUAL

TM 55-1520-210-10 OPERATORS MANUAL

TM 55-1520-210-23-1/-2/-3 MAINTENANCE MANUAL

TM 55-1520-210-CL CHECKLIST

TM 55-1520-210-PMD PREVENTATIVE MAINTENANCE DAILY

TM 55-1520-210-PM PHASE MAINTENANCE

TM 55-2840-229-23 T53 ENGINE MAINTENANCE. MANUAL

These are not Bell Helicopter manuals, Bell Helicopter doesn\'t
maintain, update or distribute these manuals. These manuals are
available for purchase at:

NTIS- National Technical Information Service

Military Publications Department

5285 Port Royal Road

Springfield, V A 22161

[PHONE]{.underline}: 703-605-6000

800-553-6847

FAX: 703-605-6900

Email <ORDERS@NTIS.GOV>

In order to assist operators operating in the Public Use, Bell
Helicopter has developed and recommends the Overhaul and Retirement
Schedule. Unfortunately Bell Helicopter cannot assist operators in Type
Certified Restricted Category. These operators are obligated to maintain
their aircraft in accordance with the Type Certificate Holder
requirements.

The rationale behind Bell Helicopter developing this recommended
Overhaul and Retirement Schedule is to remove the Gearboxes out of a
\"On-Condition\": Airworthy Limitation. In compliance with the TM\'s an
operator is required to take an oil analysis every 25 hours and submit
for a lab analysis. Bell Helicopter is aware that all operators are not
performing this maintenance task and therefore Bell Helicopter has
developed a recommend Overhaul/Retirement schedule, it\'s only provided
to assist Public Use operators.

Regards

/Andrew L. Kelley/

Product Support Engineer

4/18/2002

**UH-1 Retirement/Overhaul Schedule 4/18/2002**

**OVERHAUL RETIREMENT ITEM PART NUMBER**

**INTERVAL INTERVAL**

**(HOURS) (HOURS)**

**Main Rotor**

> 2500 . Main rotor blade 204-011-250-5/113
>
> Assembly

10,000 Composite main rotor 205-015-150-101

> blade

3600 Main Rotor Yoke 204-011-102-17

1100 Main Rotor Hub 204-011-101-3/-5/-9

Assembly.

1200 Main Rotor Hub 204-011-101-11

Assembly

1200 Main Rotor Hub 204-012-101-139/-141

Assembly

9000 Main Rotor Grip 204-011-121-117

Note 1

5000 Plate Assembly 204-011-207-105

5000 Bolt Ms21250H06000

2400 Inboard strap fitting 204-012-102-1/5

2400 Outboard Strap Fitting 204-012-103-1

2400 Strap Pin 204-012-104-1, -3, -5

2400 Retention Strap 2601399, 204-012-112-5

Retention Strap 204-012-122-1/5

3600 Clevis 204-011-142-3

3600 Clevis 204-011-179-1

15000 Center Frame Assembly 204-011-307-11

5 Years Stabilizer Bar Tube 201-011-328-1

2400 Retention Strap 2606650

2400 Strap Fitting Inboard 204-012-102-9

Main

1200/24 months Strap Assy Main Rotor 204-310-101-101

1200/24 months Strap Assy Main Rotor 2601139

5000 Support Assembly 204-011-208-101

Transmission

1100 Transmission Assembly 204-040-016-1/-3

2000 Transmission Assembly 204-040-016-5

1500 Main input quill 205-040-263-003/-111

Assembly

1500 Mast assemblv 204-040-366-009/-015

1500 Mast Bearing AMM9122-44-101

1500 Bearing 204-040-136-7/-9

1500 Bearing 212-040-136-1

1500 Mast Assembly 204-011-450-105

1500 Mast Assembly 204-011-450-7

**Tail Rotor & Drive**

**System**

1100 Blade Assembly 204-011-702-11

1200 Blade Assembly 204-011-702-15

1000 Blade Assembly 204-011-702-121

Note #2

> 1

**OVERHAUL RETIREMENT ITEM PART NUMBER**

**INTERVAL INTERVAL**

**(HOURS) (HOURS)**

**Tail Rotor & Drive**

**System (Continued)**

300 Grip Assembly 204-011-728-1

300 Grip Assembly 204-011-728-19

2500 Grip Assembly 205-011-711-101

1500 Yoke Assembly 204-011-722-5

1500 Gearbox 42° 04-040-003-7/-13

-19, -23, -29

3000 Slider, Tail Rotor 204-010-720-3

600 . Bearing Hanger 204-040-623-5 or

PAM9107NPPA2702

600 Gearbox 90° 204-040-012-1

1200 Gearbox 90° 204-040-012-7

1200 Gearbox 90° 204-040-012-13

**Main Rotor Mast**

**Controls**

1100 Swashplate & Support 204-011-400-1/-3/-5/-7/-9

Assy

1200 Swashplate & Support 204-011-400-11

Assy

ON CONDITION Scissors and Sleeve 212-010-400-129

Assembly Note 3

9000 Outer Ring 204-011-403-001

Note 3

1000 Support 204-011-404-125

Note 3

9000 Outer Ring 204-011-403-001

1000 Support 204-011-404-125

3300 Support 204-011-404-1

3600 Support 204-011-404-5

500 Pin 204-011-446-3

4800 Collective Lever 212-010-403-5

1000 Collective Lever 204-011-438-1

3600 Scissors Assembly 204-011-406-1/-9/-13/-15

1100 Scissors and Sleeve 204-011-401-1/-7/-9

Assembly

1200 Scissors and Sleeve 204-011-401-011

Assembly

ON CONDITION Scissors and Sleeve 212-010-401-021

Assembly Note 4

9000 Scissors & Hub 204-011-405-013

Note 4

9000 Drive Link 204-011-407-001

Note 4

9000 Collective Sleeve 204-011-408-105

Note 4

ON CONDITION Scissors lever 212-010-407-109

assembly

9000 Scissors Hub 204-011-405-021

9000 Drive Link 204-011-407 -001

9000 Collective Sleeve 204-011-408-105

2

**Notes:**

#1. Reference BHT Technical Bulletin SU 95-5, Alternate Spare Part: Main
Rotor

Grip PIN 204-011-121-117

#2. Reference BHT Technical Bulletin SU94-2, Alternate Spare Part: Tail
Rotor

Blade PIN 204-011-702-121

#3. Reference BHT Technical Bulletin SU 95-4, Alternate Spare Part,
Swashplate and

Support Assembly

#4. Reference BHT Technical Bulletin SU-94-3, Alternate Spare Part and
Scissor and

Sleeve Assembly PIN 204-011-401-021

3