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FMS/RNAV/Autopilot Interface: Display and Controls (Part One)

by Flight Learnings

in Navigation

Every avionics device has a display and a collection of buttons, keys, and knobs used to operate the unit. The display allows the device(s) to present information. The controls allow the pilot to enter information and program the avionics to accomplish the desired operations or tasks. The display and controls for a typical FMS are shown in Figure 3-2.

Figure 3-2. FMS display and controls.

Figure 3-2. FMS display and controls.

Accessing Information in the FMS

FMS units contain much more information than they can present on the display at any one time. Information pertaining to some topics often extends beyond what can be presented on a single page. Page groups, or chapters, solve this problem by collecting all of the pages pertaining to the same topic. Each page presents information about a particular topic, and bears a page title reflecting its content. For example, the airport chapter may be divided into several airport pages, each page displaying different information about that airport. One page might be navaids. Another page might be the airport taxiway diagram. Yet another airport page might indicate available services and fixed-base operators. Review the documentation for that specific unit and installation to determine what information and levels of data are available and require updates. Usually, only one page can be displayed at a time. The airport page is displayed on the FMS in Figure 3-3.

Figure 3-3. Pages and page groups (chapters).

Figure 3-3. Pages and page groups (chapters).

Figure 3-3 shows how to access pages and chapters on one manufacturer’s FMS. Different FMS units have different ways of allowing the pilot to switch between chapters and pages, and different ways of informing the pilot which chapter and page is currently displayed.

Making Entries in the FMS

To enter data, you use the FMS buttons (keyboard or individual) and knob controls, or a data source, such as disk media or keypad, as shown in Figure 3-4.

Figure 3-4. An FMS keypad.

Figure 3-4. An FMS keypad.

FMS units that do not feature keypads typically require the pilot to make entries using the same knobs to move among chapters and pages. In this case, the knobs have multiple purposes and, thus, have different modes of operation. To use the knobs for data entry, you must first activate what some manufacturers call the “cursor” (or “data entry”) mode. Activating the cursor mode allows you to enter data by turning the knob. In other units, after activating the data entry mode, entries are made by pushing buttons.

Figure 3-5 illustrates the use of cursor mode to enter the name of an airport using one FMS. Pressing the inner knob engages cursor mode. A flashing cursor appears over one of the items on the page, indicating that it is ready for editing. Then, the inner knob is used to dial letters and numbers; the outer knob is used to move the flashing cursor between items on the page.

Figure 3-5. Making entries using cursor mode.

Figure 3-5. Making entries using cursor mode.

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