Download the X-Plane 10 Manual - X-Plane.com

7.1. NAVIGATING 73
• Textured—a nice map that is not used in pilot circles. This overlays the X-Plane terrain
images on top of the navigation charts to give the user a good bird’s eye view of the area he
or she is flying over.
Note that the maps in X-Plane are covered in more detail in the section “Using X-Plane’s
Navigation Maps” later in this chapter.
7.1.2.1 NDB Navigation
Non-directional beacons were invented in the late 1940s and consisted of a ground-based transmitter
that broadcast a homing signal. A receiver in the aircraft could be tuned to one of about 300 discrete
frequencies in order to tune to a particular transmitter. With that done, an instrument in the panel,
called the NDB (or, interchangeably, the ADF, or Automatic Direction Finder), would point to the
station. This system was a large technological leap forward over the older aural-based system and
was actually quite easy to use, provided that the wind was perfectly calm or blowing in a direction
that was exactly parallel to the direction of flight. Of course, that pretty much never happened,
resulting in the aircraft always being blown off course. As a result, the pilots had to watch the trend
of movement in the needle over a relatively long period of time (e.g., five to eight minutes) to see
if the angle to the station that was depicted stayed constant or was changing. If it was changing,
it indicated that the aircraft was being blown off course and the pilot had to turn in the opposite
direction by half of the deviation. After holding that heading for another five minutes or so the
pilot would again observe the relative trend of the needle and correct again.
The trick was to fly as straight as possible from one station to another. Although nearly abandoned
in the United States, NDBs are still used in many countries around the world. It is for this
reason that they are modeled in X-Plane.
An ADF is located in the instrument panel for the Cessna 172 that comes with X-Plane. It is
located above the mixture knob and trim wheel, below the dual VOR CDIs.
7.1.2.2 VOR Navigation
Very High Frequency Omni-Range navigation (or VOR) was introduced in the mid-1950s and
represented a large improvement in navigation accuracy. Instead of an NDB that a pilot could
home in on, the VOR sends a series of 360 discrete little carrier tones on a main frequency. Each
of these carriers is oriented along a different radial from the station, one of 360 just like a compass
rose. Thus, when you are flying along and tune in the main VOR frequency, you then fine tune your
navigation display to tell you which of the 360 radials you are flying and also whether the transmitter
station is in front of or behind you. Impressive! This finally gave pilots a means of telling exactly
where they were in relation to a fixed spot on earth, and this system “automatically” adjusted for
any winds aloft as the system would quickly display any error in track that the plane was making.
This error could only be due to two factors—either the pilot was not flying along the radial or the
wind blew the airplane slightly off of course. VORs are modeled in X-Plane.
VOR stations appear in the X-Plane maps as relatively large circles with notches around the
edges, similar to a clock face. They are tagged with boxes that have their name and identifier on
the left side and their VOR frequency on the right.
A specific type of VOR, a VOR-DME, combines the lateral guidance (that is, guidance left and
right) of a VOR with the distance guidance of a DME (distance measuring equipment). Another
type of VOR beacon, a VORTAC, is also found throughout the X-Plane maps. This is a transmitter
that combines both VOR and TACAN features. TACAN (or tactical air navigation) provides