Cessna 172P - Page 275

PILOT'S
OPERAÎING
HANDBOOK
SUPPLEMENT
12
FOSTER,
AN,EA NAVIGATION
(TYPE
511)
sEciloN
4
NORMAL
OPERATION
VOR/LOC
OPERATION
VOR,
NAVIGATION
CIRCUTTS
VERIFICATION
TESTS:
1. See
appropriate
Nav/Com
supplement.
AREA
NAVIGATION
OPERATING
NOTES
1.
Ioss may
be
experienced
enroute.
2. When
a
waypoint
from one
VORTAC
is
displaoed
over
a second
VORTAC,
interfereuoe
from the
seoond
VORTAC
eometimes
causes
erratio
and unusabte
BEARING
and
RANGE
displays
on
the F,NAV
at
low altitude.
3.
The
RNAV
BEARING
readout
(to
the waypoint)
becomes
extremely
sensitive
aud
may
become
unusable
within
t
'
L LIZ
miles
of the waypoint.
Thus,
the
RANGE
readout
is the
primary
means
of
approximating
waypoint
passage'
4.
Tracking
from a waypoint
is not reoommended
since
the
pilot
would
have to
fty a reciprocal bearing
and make
error oorrections
in the opposite
direotion
from
flying to a waypoint.
DIAGNOSTIC
FUNCTIONS
All
RNAV
systems ars rendered
inoporative
under certain
conditions.
The
RNAV
õ11
provides
a
Flag mode and
permits
a diagnostic
interpreta-
tion of why
the system
is inoperative.
FLAG MODE
INDICATIONS:
Six
"Bars" Appear in the Digital Displays
(2
&
6):
a. PRESS VOR/DME button
(õ)
to determine
if the
VOR, radial
signal
is abeeut,
If VOR
radial signal
is absent,
bars wíll
change
to
show &s
"000"
in
the BEARING
window
(2).
(One
possible
cause of this condition could be
that the
NAV
receiver
is channeled to a localizer signal.)
1
õ
30
May
1980