Page 139 - Planning and Design of Airports

108 Airp o r t Pl anning

Victor Airways
Following the development of the LF/MF four course radio ranges
the routes now known as the victor airways were established. The
victor airways are delineated on the ground by very high frequency
omnirange radio equipment (VORs). Each VOR station has a discrete
radio frequency to which a pilot could tune a navigational radio and
thus be able to maintain a course from one VOR to the next. The num-
bering system for these airways is even numbers east and west, odd
numbers north and south. The advantages of the victor airways were
that the VORs were relatively free of static and it is much easier for a
pilot to determine air position relative to a VOR station than with the
LF/MF four course radio range. Victor airways are designated on
aeronautical charts as V-1, V-2, etc. The airway includes the airspace
within parallel lines 4 mi each side of the centerline of the airway. If
two VORs delineating an airway are more than 120 mi apart, the air-
space included in the airway is as indicated for jet routes.

Jet Routes
With the introduction of commercial jet aircraft in 1958, the altitudes
at which these aircraft flew increased significantly. At higher altitudes
the number of ground stations (VORs) required to delineate a specific
route is smaller than at lower altitudes because the signal is transmit-
ted on a line of sight. Therefore there was no need to clutter the high
altitude routes with all the ground stations required for low altitude
flying. All the routes in the continental United States could be placed
on one chart. These were established what are known as jet routes.
Although in one sense these routes are airways, they are not referred
to as such. Today both victor airways and jet routes exist. Thus the jet
routes are delineated by the same aids to navigation on the ground
(VORs) as are victor airways but fewer stations are used. Victor air-
ways extend from 1200 ft above the terrain to, but not including,
18,000 ft AMSL. Jet routes extend from 18,000 ft to 45,000 ft AMSL.
Above 45,000 ft there are no designated routes and aircraft are han-
dled on an individual basis. The numbering system for the jet routes
is the same as for the victor airways. Jet routes are designated on
aeronautical charts as J-1, J-2, etc.

Area Navigation
For many years all aircraft were required to fly on designated routes,
airways, or jet routes. That is, all aircraft had to fly from one VOR to
the next VOR since the VORs delineate the airways and jet routes.
This required the funneling of all traffic on the designated routes that
resulted in congestion on certain routes. Also the designated routes
were often not the shortest distance between two points, resulting in
additional fuel consumption, flight time, and cost. Furthermore, if the