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Subcourse No. AL0993

US Army Aviation Logistics School
Fort Eustis, Virginia

19 Credit Hours


Fulfilling the Army's need for engines of simple design that are easy to operate and maintain, the gas turbine engine is used in all helicopters of Active Army and Reserve Components, and most of the fixed-wing aircraft to include the Light Air Cushioned Vehicle (LACV).

We designed this subcourse to teach you theory and principles of the gas turbine engine and some of the basic army aircraft gas turbine engines used in our aircraft today.

There are no prerequisites for this subcourse.

This subcourse reflects the doctrine which was current at the time it was prepared. In your own work situation, always refer to the latest publications.


Aircraft designers have always been limited by the efficiency of the available powerplants. Their constant plea has been for higher power, less weight, lower frontal area, better cooling characteristics, and lower fuel consumption. These requirements have been met to a certain degree by the designers of reciprocating engines, but the design of the piston engine has been carried to such a point that to obtain further increase in power, more cylinders would have to be added. This would immediately raise more complex problems, which must be solved before an increase in power can be achieved.

The aircraft designers' pleas have been answered with the development of the gas turbine engine. Since the end of World War II, progress in the gas turbine field has been rapid. Development of improved materials, high temperature metals, and better fuels should expedite further progress in this held. The gas turbine engine's greatest contribution to aviation is that it has lifted all previous limits that were imposed by the reciprocating engine.

This text describes the operation, components, and systems of the gas turbine engine. The first two lessons includes an introduction to gas turbine engines. Lesson 3 discusses the systems and accessories such as fuel, oil, and electrical. Lesson 4 covers testing, inspection, maintenance, and storage procedures. Lesson 5 through 8 describe in detail the gas turbine engines used in Army aircraft.


ACTION: You will describe the operation of major engine systems and assemblies; describe the testing, inspection, and maintenance of engine systems and assemblies; and recognize various components.
CONDITION: Given information about the gas turbine engine, you will work at your own pace in an environment of your own choice, without supervision.
STANDARD: To demonstrate competency of this task, you must achieve a minimum of 70% on the subcourse examination.



  1   Theory and Principles of Gas Turbine Engines


2 Major Engine Sections


3 Systems and Accessories


4 Testing, Inspection, Maintenance, and Storage Procedures


5 Lycoming T53


6 Lycoming T55


7 Solar T62 Auxiliary Power Unit


8 Allison T63, Pratt & Whitney T73 and T74, and the General Electric T700







Table of Contents

Lesson 1   Theory and Principles of Gas Turbine Engines
  Practice Exercise
Lesson 2 Major Engine Sections
  Practice Exercise
Lesson 3 Systems and Accessories
  Practice Exercise
Lesson 4 Testing, Inspection, Maintenance, and Storage Procedures
  Practice Exercise
Lesson 5 Lycoming T53
  Practice Exercise
Lesson 6 Lycoming T55
  Practice Exercise
Lesson 7 Solar T62 Auxiliary Power Unit
  Practice Exercise
Lesson 8 Allison T63, Pratt & Whitney T73 and T74, and the General Electric T700
  Practice Exercise

Appendix I: References

Appendix I: Glossary


AL0993 Edition 5 Examination