INDICATORS

CHAPTER 5 INDICATORS In this chapter, we will discuss the various types of indicators in use today. These indicators range from the heading indicators to the newest heads-up display (HUD) tactical displays. Every effort was made to include as many different platforms as possible. HEADING INDICATORS Learning Objective: Identify the types of heading indicators and their primary functions. The two heading indicators that we will be discussing are the horizontal situation indicator (HSI) and the bearing-distance-heading indicator (BDHI). Both of these indicators are used on many different types of aircraft. The information displayed by these indicators comes from the various navigational systems on the aircraft. The HSI displays more information than the BDHI. HORIZONTAL SITUATION INDICATOR The HSI system we will discuss is the system in use on the P3-C aircraft. The HSI group provides the pilot, copilot, and NAV/COMM operator with a visual display of aircraft course, bearing, heading, and distance to a selected point. System Components The HSI group consists of three ID-1540/A indicators and three control boxes. The three control boxes are the pilot’s control, copilot’s control, and the NAV/COMMs control. The three ID-1540/As are interchangeable between the three stations, but the control boxes are not. ID-1540/A HORIZONTAL SITUATION INDICATOR.— The ID-1540/A indicator (fig. 5-1) is a multipurpose aircraft situation indicator. It keeps the pilot, copilot, and the NAV/COMM operator informed of the aircraft’s situation at any given moment. Refer to figure 5-1 while reading the following text. 1. The lubber line is the reference line for reading the aircraft’s heading on the compass card. 2. Bearing pointer 1 points to the bearing of the selected navigational point. 3. The heading marker indicates the desired heading as set by the HEADING SET knob. 4. The course arrow indicates the course set by the COURSE SET knob in the radio navigation mode. This arrow indicates the course set by the computer in the tactical navigational mode. 5. The COURSE indicator displays, in degrees, a digital readout of the course arrow setting. 6. The mode lights indicate the operating mode selected on the HSI control box for that station. 7. The course deviation bar indicates deviation relative to the course arrow position for VOR or Figure 5-1.-ID-1540/A horizontal situation indicator. 5-1