TM 55-2840-241-23
Change 19 1-1/(1-2 blank)
CHAPTER 1
INTRODUCTION
Section I. GENERAL
1-1. Scope.
a.
This manual is issued expressly for Aviation Unit
Maintenance (AVUM) and Aviation Intermediate Mainte-
nance (AVIM) activities. Its purpose is to familiarize main-
tenance personnel having limited technical training and
experience with the maintenance functions to be per-
formed on the Army Model T63-A-720 (Allison Gas Tur-
bine Model 250-C20C) turboshaft engine. The study and
use of this manual will enable maintenance personnel to
perform the assigned functions with maximum efficiency.
This manual provides all essential information to accom-
plish the three levels of maintenance on the complete
engine, its components, and systems as prescribed in
the Maintenance Allocation Chart (MAC). (Refer to Ap-
pendix B.)
CAUTION
Use only chrome plated steel or unplated
steel tools for the disassembly or reas-
sembly procedures described in this
manual. The use of cadmium or zinc
plated tools is not permitted since these
platings are prone to chipping and flaking.
Should these chips enter the engine they
may contaminate the lubrication system,
ultimately clogging the filters or produce
intergranular attack on nickel or titanium
base alloys at elevated temperatures.
1-2. Maintenance Forms and Records.
Maintenance forms, records, and reports which are to
be used by maintenance personnel at all maintenance
levels are listed in and prescribed by DA Pamphlet
738-751, Functional Users Manual for the Army Mainte-
nance Management System - Aviation (TAMMS-A).
1-3. Reporting of Errors.
Reports of errors, omissions, and recommendations
for improving this publication by the individual user is
encouraged. Reports shall be submitted on DA Form
2028 (Recommended Changes to Publication and Blank
Forms) or DA Form 2028-2 located in the back of this
manual directly to Commander, U.S. Army Aviation and
Missile Command, ATTN: AMSAM-MMC-LS-LP, Red-
stone Arsenal, AL 35898-5230. You may also submit
your recommended changes by E-Mail directly to ls-
lp@redstone.army.mil or by fax (256) 842-6546/DSN
788-6546. A reply will be furnished directly to you. In-
struction for sending an electronic 2028 may be found at
the back of this manual immediately preceding the hard
copy 2028.
1-4. Destruction of Army Material to Prevent Enemy
Use.
Procedures for destruction of Army materials to pre-
vent enemy use are prescribed by TM 750-244-1-5.
