Cessna TURBO CENTURION T210M 1978 Pilot Operating Handbook page 318

CESSNA 800 ALTITUDE PILOT'S OPERATING HANDBOOK
ENCODING/ ALERTING/PRESELECT SUPPPLEMENT
removed from the altimeter, a striped warning flag appears across the
digital altitude display to indicate a "power-off" condition.
The local altimeter setting is set into the altimeter with a manually
operated baroset knob, and is displayed on a four-digit readout, either in
inches of mercury or in millibars (as ordered). The altimeter setting does
not affect the output of the optical encoder, since the encoder is always
referenced to standard pressure (sea level; 29.92 inches of mercury or
1013.2 millibars).
Except for introducing the altimeter setting with the baroset knob,
operation of the altimeter is completely automatic. The baroset knob and
the display indicators are shown in Figure
1.
The altitude alerter is a panel-mounted unit which includes all of the
operating controls and indicators and the preselector logic circuits.
Altitude information for use in the altitude alerter is supplied electroni-
cally from the encoding altimeter. Three Minilever switches, mounted on
the front panel of the unit, are used to select any altitude between 100 and
35,000 feet in 100-foot increments; the selected altitude is displayed on a
digital readout. The preselector control and indicators and an ALERT
indicator are also included on the front panel of the unit. All controls and
indicators for the altitude alerter are shown in Figure 2.
The altitude capture function is selected by a white pushbutton switch
(ARM) which energizes the preselector logic circuits. For altitude capture
function operation, the Integrated Flight Control System must be turned
on but not engaged in a vertical mode (altitude hold or glide slope coupled).
When the Minilever switches are set to the desired altitude and the white
ARM pushbutton is pushed in, an amber ARMD panel lamp lights to
indicate that the function is "armed." When the airplane reaches the
selected altitude, the amber ARMD lamp turns off, and a green CPLD panel
lamp on the alerter and the altitude hold (ALT) lamp on the flight director
mode selector lights to indicate that altitude hold mode is operational.
If
the Minilever switches are repositioned after the preselector has been
armed but before altitude hold is engaged, the logic circuits are reset and
must be rearmed by again pushing in the ARM switch.
The alert indicator consists of a three-lamp display and an associated
one-second aural tone. The green indicator lamp (ALERT) lights when the
airplane altitude is within ±300 feet of the selected altitude. When the
airplane enters an altitude band from 300 to 1000 feet above or below the
selected altitude, the amber HI ALERT or LO ALERT lamp lights and
simultaneously, a one-second tone is heard. The one-second aural annun-
ciator is only activated whenever the amber altitude band is entered, or the
green altitude band is departed. There is no audible annunciator when the
green band is entered, or when the amber altitude band is departed.
2
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