Textron 172R180HP, Pilot Operating Handbook

Page: 228 / 396

SECTION 7
AIRPLANE & SYSTEMS DESCRIPTION
CESSNA
MODEL 172R (180 HP}
CABIN HEATING, VENTILATING AND
DEFROSTING SYSTEM
The temperature and volume of airflow into the cabin can be
regulated by manipulation of the push-pull CABIN HT and CABIN
IAIR controls (Refer to Figure 7-8). Both controls are the double­
button locking type and permit intermediate settings.
For cabin ventilation, pull the CABIN AIR knob out. To raise the
air temperature, pull the CABIN HT knob out approximately 1/4 to
1/2 inch for a small amount of cabin heat. Additional heat is
available by pulling the knob out farther; maximum heat is available
with the CABIN HT knob pulled out and the CABIN AIR knob
pushed full in. When no heat is desired in the cabin, the CABIN HT
knob is pushed full in.
Front cabin heat and ventilating air is supplied by outlet holes
spaced across a cabin manifold just forward of the pilot's and
copilot's feet. Rear cabin heat and air is supplied by two ducts from
the manifold, one extending down each side of the cabin to an
loutlet
just aft of the rudder pedals at floor level. Windshield defrost
air is also supplied by two ducts leading from the cabin manifold to
defroster outlets near the lower edge of the windshield. Two knobs
control sliding valves in either defroster outlet to permit regulation of
defroster airflow.
Separate adjustable ventilators supply additional air; one near
each upper corner of the windshield supplies air for the pilot and
copilot, and two ventilators are available for the rear cabin area to
supply air to the rear seat passengers. Additionally, there are
ventilators located on the forward cabin sidewall area just below the
windshield sill area.
7-40
Oct 4/01