Chapter 5: Engine Instrumentation and Fire Detection Systems

CHAPTER FIVE

ENGINE INSTRUMENTATION AND FIRE DETECTION SYSTEMS

500.

INTRODUCTION

As student aviators, it is necessary for you to become familiar with the T-34C instrumentation

and fire detection system. You must also become familiar with the location and operation of

various components in order to ensure your capability to operate the aircraft safely and

efficiently.

501.

LESSON TOPIC LEARNING OBJECTIVES

Terminal Objective

5.0 Upon completion of this chapter, the student will demonstrate knowledge of the PT6A-25

instrumentation and fire detection systems characteristics.

Enabling Objectives

5.1

State the purpose of the interstage turbine temperature (ITT) sensing system.

5.2 Describe the location and purpose of the interstage turbine temperature sensing system,

indicators and system limitations.

5.3

Describe the location, purpose and display indications of the turbine tachometer.

5.4

Explain the compressor turbine (N1) limitations.

5.5

Explain the purpose of the fire detection system.

5.6 Describe the location and method of operation of the components of the fire detection

system.

502.

ENGINE INSTRUMENATION

Interstage Turbine Temperature

The ITT sensing system provides an accurate indication of engine operating temperature. Eight

thermocouples are attached to a harness in the engine interior and protrude into the area between

the compressor and power turbines. Each thermocouple is a bi-metallic metal probe that creates

an electrical current proportional to the temperature detected. The current operates the ITT

indicator in each cockpit.

The ITT indicators, located on the instrument panels in both cockpits, are powered by the

electrical signal from the thermocouples. The gauge is graduated in 20 C increments between

200 and 1200 degrees Centigrade.

ENGINE INSTRUMENTATION AND FIRE DETECTION SYSTEMS

5-1