Textron 172R180HP, Pilot Operating Handbook

Page: 84 / 396

SECTION 3 CESSNA
MODEL 172R (180 HP)
EMERGENCY PROCEDURES
INSUFFICIENT RATE OF CHARGE
NOTE
Illumination of the low voltage (VOL TS) annunciator and
ammeter discharge indications may occur during low RPM
conditions with an electrical load on the system, such as
during a low RPM taxi. Under these conditions, the light will
go out at higher RPM.
If the overvoltage sensor should shut down the alternator and trip
lthe alternate circuit breaker (ALT FLO), or if the alternator output is
low, a discharge rate will be shown on the ammeter followed by
illumination of the low voltage (VOL TS) annunciator. Since this may
be a "nuisance" trip out, an attempt should be made to reactivate
l
the alternator system. To reactivate, turn the avionics master switch
off, check that the alternator field circuit breaker (ALT FLO) is in,
then turn both sides of the master switch off and then on again. If
the problem no longer exists, normal alternator charging will resume
land the low voltage annunciator (VOL TS) will go off. The avionics
master switch may then be turned back on.
I
If the annunciator illuminates again, a malfunction is confirmed.
In this event, the flight should be terminated and/or the current drain
on the battery minimized because the battery can supply the
electrical system for only a limited period of time. Battery power
must be conserved for later operation of the wing flaps and, if the
emergency occurs at night, for possible use of the landing lights
during landing.
OTHER EMERGENCIES
WINDSHIELD DAMAGE
If a bird strike or other incident should damage the windshield in
flight to the point of creating an opening, a significant loss in
performance may be expected. This loss may be minimized in some
cases (depending on amount of damage, altitude, etc.) by opening
the side windows while the airplane is maneuvered for a landing at
the nearest airport. If airplane performance or other adverse
conditions preclude landing at an airport, prepare for an "off airport·
landing in accordance with the Precautionary Landing With Engine
Power or Ditching checklists.
3-22
Oct 4/01