The Journey of Flight.pdf - Valkyrie Cadet

Chapter Chapter Chapter 9 9 - - Flight Flight Navigation
Navigation
Radials Broadcast by a VOR Station
Therefore, all the pilot has to do is align the nose of the airplane with the needle and flight will then be
toward the broadcasting station.
There are several problems with the use of the ADF as compared to the VOR. The ADF display
does not compensate for the effect of wind. The airplane might follow a curved instead of a straight
course to the station, if the pilot does not manually turn into the wind to avoid drift. Signals in the
frequency range used by the ADF will give incorrect directional information to the ADF receiver
occasionally because they bounce off of land features much like an echo.
With all of its drawbacks, the ADF system is a useful aid to navigation. It still provides some
directional information to pilots, helping them if they cannot see the ground. It just requires more work
by the pilot to fly precise routes between points.
Distance-Measuring Equipment (DME). Many of the VOR stations across the country have a
special unit called tactical air navigation (TACAN). When this unit is installed with a VOR, the station
is called a VORTAC.
The TACAN portion will respond with a broadcast signal when it receives a signal from the DME
unit in the airplane. The DME sends a signal and measures the time it takes to go from the aircraft to
the VORTAC and return. The DME unit converts the time to nautical miles distance between the
airplane and the station.
The VOR receiver is tuned to the same VORTAC as the DME unit. The VOR shows which radial
the airplane is on and whether the flight is to or from the station. The DME tells how far away the
airplane is at any given moment. So now, the pilot not only knows which direction he is from a ground
station, like an ADF, but can plan to fly on a particular radial and knows how far it is to the station. This
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