Instrument Flight
Flight Procedures
Indications Of Station Passage
When flying VOR or VOR/DME, station passage is indicated when the bearing pointer falls past the
90 degrees reference benchmark on the periphery of the compass rose.
TACAN station passage, due to increased size of the cone of confusion associated with TACAN stations,
is noted when minimum DME is reached.
WIND DRIFT CORRECTION
Determining wind-corrected heading (WCH) is the technique you will use to compensate for crosswinds
when maintaining a course on a radial. To compensate for wind, use a WCH that stops drift from your
course. The difference between WCH and desired course is called “crab angle” (Figure 16).
The difference between the lubber line and the ground track marker is your “crab angle.” To compensate
for crosswinds using the ground track marker, first establish the aircraft on a radial tracking on course,
course line centered, inbound or outbound from a station. Check the position of the ground track marker
for an indication of drift. If the ground track marker indicates a drift, turn the aircraft to place the ground
track marker under the bearing pointer. Maintain the heading under the lubber line. Continuously monitor
the course line to ensure that you are
maintaining the desired course. Adjust
your heading to maintain a centered
course line. The amount of crab angle
required will vary with wind strength
and direction and may change while
the course is being tracked.
D.
COURSE INTERCEPTS
It is sometimes necessary to change
WIND
positions or radials inbound to or
outbound from a facility. Both inbound
and outbound course intercepts are
basically the same in that you must
determine the angle of intercept to
A.
Aircraft on course
C.
achieve the most expeditious intercept
and on heading
of the desired radial.
B.
Aircraft drifts off course
The angle of intercept is the angle
while remaining on heading
between the heading of your aircraft
and the desired course; it is normally
C.
Heading changed to
greater than the number of degrees
reintercept course
you are from your desired course, but
it must not exceed 90 degrees. At
D.
Heading adjusted into wind
90 degrees, the rate of interception is
to keep CDI centered
B.
the maximum possible. Within these
two limits, you can adjust your
intercept angle to achieve the most
desirable rate of interception.
Lead point for course intercepts is
A.
calculated as 1 percent of your ground
speed for an intercept angle of
90 degrees. For intercept angles of
Figure 16: WIND DRIFT CORRECTION
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