VOR/DME RNAV

1
VOR/DME RNAV

• AST 241 Chapter 5

2
VOR'

• Following VOR (Victor) airways on average results
  in 7 percent greater distance traveled point to
  point
• VOR/DME RNAV developed in the late 1960s to
  alleviate this problem

3
RNAV Theory

• Course Line Computer (CLC)- takes VOR DME input
  and creates phantom waypoints in a straight
  line between any two points within range of the
  associated VORs

4
RNAV Theory

• Waypoints can be entered either of two ways
• Radial/Distance- Most Common, p.92 in text
• Lat./Long.
• Some units can hold 50 to 100 waypoints along
  different routes

5
RNAV Theory

• RNAV course- called a desired track
• CDI sensitivity changes from enroute mode- one
  dot deflection 1NM off course to approach mode-
  one dot deflection a fraction of a mile
  (varies)
• With RNAV the CDI sensitivity dosent change with
  distance from the waypoint- remains constant

6
RNAV Applications- VFR

• Airport Finder
• Random routings
• Descent manager

7
RNAV Applications- IFR

• Direct routes- easier to get once airborne- can
  ask for an initial on course heading from ATC
• File /R on flight plan (usually)
• Must be in RADAR contact for IFR nav.
• No formal RNAV routing system in use today
• At least one waypoint every 200 NM

8
RNAV-IFR (ctn.)

• Unit must meet AC 90-45
• Use standard arrival and dep. Routings
• Use at least one route defining waypoint per
  ARTCC boundary and one no farther than the
  previous center boundary
• Must circumnavigate restricted airspace by at
  least 3 NM
• Flight above FL 390 must lat./long. wpts.

9
RNAV- IFR (ctn.)

• To find intersections- simply input the
  intersection as a waypoint and navigate direct to
• Helpful to navigate along NDB airways and as a
  route cross-check along a Victor airway

10
RNAV Future

• Will be around for as long as the VHF airway
  system is in use F(at least until the year 2010).
• After that- ?