Cessna 1980 172RG Cutlass Pilot Operating Handbook Download

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DIGITAL CLOCK

PILOT'S OPERATING HANDBOOK

MODEL 172RG

SUPPLEMENT

Pressing the

button two additional times will cause the time to

appear with the hours digits flashing. Using the

button as before,

advance the hour digits to the correct hour as referenced to a known time
standard. Another push of the

button will now cause the minutes digits

to flash. Advance the minutes digits to the next whole minute to be reached
by the time standard and "hold" the display by pressing the

button once

more. At the exact instant the time standard reaches the value "held" by the

display, press the

button to restart normal clock timing, which will

now be synchronized to the time standard.

In some instances, however, it may not be necessary to advance the

minutes digits of the clock; for example when changing time zones. In such

a case, do not advance the minutes digits while they are flashing. Instead,
press the

button again, and the clock returns to the normal time

keeping mode without altering the minutes timing.

TIMER OPERATION

The completely independent 24-hour elapsed timer (see figure 3) is

operated as follows: press the center (MODE) push button until the timer

mode indicator appears. Reset the display to "zero" by pressing the

button. Begin timing an event by pressing the

button. The timer will

begin counting in minutes and seconds and the colon (activity indicator)
will blink off for 1/ 10 second each second. When 59 minutes 59 seconds
have accumulated, the timer changes to count in hours and minutes up to a

maximum of 23 hours, 59 minutes. During the count in hours and minutes,
the colon blinks off for one second each ten seconds. To stop timing the
event, press the

button once again and the time shown by the display is

"frozen". Successive pushes of the

button will alternately restart the

count from the "held" total or stop the count at a new total. The hold status

of the timer can be recognized by lack of colon activity, either continuously

on or continuously off. The timer can be reset to "zero" at anytime using the

button.

SECTION 5

PERFORMANCE

There is no change to the airplane performance when the digital clock

is installed.

1 July 1979

PILOT'S OPERATING HANDBOOK

GROUND SERVICE PLUG

SUPPLEMENT

RECEPTACLE

MODEL 172RG

SUPPLEMENT

GROUND SERVICE

PLUG RECEPTACLE

SECTION 1

GENERAL

The ground service plug receptacle permits the use of an external

power source for cold weather starting and lengthy maintenance work on
the electrical and electronic equipment. The receptacle is located behind a
door on the left side of the fuselage aft of the baggage compartment door.

NOTE

If no avionics equipment is to be used or worked on, the
avionics power switch should be turned off. If maintenance
is required on the avionics equipment, it is advisable to

utilize a battery cart external power source to prevent
damage to the avionics equipment by transient voltage. Do
not crank or start the engine with the avionics power
switch turned on.

The battery and external power circuits have been designed to com-

pletely eliminate the need to "jumper" across the battery contactor to close

it for charging a completely "dead" battery. A special fused circuit in the

external power system supplies the needed "jumper

across the contacts

so that with a "dead" battery and an external power source applied, turning

the master switch ON will close the battery contactor.

1 July 1979

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