Cessna 172SPHUSR05 Pilot Operating Handbook page 287

CESSNA
MODEL 172S
Fl
8
1. IDENT SUDON (lOT) - When depressed, selects special
identifier pulse to be transmitted with transponder reply to
effect immediate identification of the airplane on the ground
controller's
approximately 18 seconds. Sutton illumination is controlled by
the avionic light dimming rheostat.
2. ALTITUDE DISPLAY - Displays the pressure altitUde on the
left side of the display.
nFLu is annunciated to indicate Flight Level altitude.
Level is a term to indicate that the altitude is not true altitude,
but barometric altitude which is not corrected for local
pressure. For Example, nFL-040tl corresponds to an altitude
of 4000 feet, meaning sea level pressure of 29.92 inches of
mercury.
The Flight Level altitude is only displayed when the altitude
reporting is enabled, i.e. in Altitude mode. If an invalid code
from the altimeter is detected dashes will appear in the
altitude window.
window is blank or has dashes.
Figure 1. Bendix/King KT
July
8/98
SUPPLEMENT 2 - FAA APPROVED
3 4
1200
display. C'Rn
The display is in hundreds of feet.
Altitude reporting is disabled if the altitude
Transponder with Blind Encoder
76C
(Sheet 1 of 2)
SECTION 9 - SUPPLEMENTS
7
will illuminate steadily
6
for
Flight
S2-5