Icing; Inadverted Icing Encounter; Static Source Blockage - Cessna 172 P Pilot Operating Handbook

SECTION: | 1 | 2 | 3 |
ICIN G

INADVERTED ICING ENCOUNTER

[1] Turn pitot heat switch ON (if installed)
[2] Turn back or change altitude to obtain an outside air tempera-
ture that is less conductive to icing.
[3] Pull cabin heat control full out and open defroster outlets to
obtain maximum windshield defroster airflow. Adjust cabin air
control to get maximum defroster heat and airflow.
[4] Open the throttle to increase engine speed and minimize ice
build up on propeller blades.
[5] Watch for signs of carburetor air filter ice and apply carburetor
heat as required. An unexplained loss in engine speed could be
caused by carburetor ice or air intake filter ice. Lean the mix-
ture for maximum RPM, if carburetor heat is used continously.
[6] Plan a landing at the nearest airport. With an extremely rapid
ice build-up, select a suitable „off airport" landing site.
[7] With an ice accumulation of 1/4 inch or more on the wing
leading edges, be prepared for significantly higher stall speed.
[8] Leave wing flaps retracted. With a severe ice build-up on the
horizontal tail, the change in wing wake airflow direction
caused by wing flap extension could result in a loss of elevator
effectiveness.
[9] Open left window and, if practical, scrape ice from a portion of
the windshield for visibility in the landing approach.
[10] Perform a landing approach using a forward slip, if necessary,
for improved visibility.
[11] Approach at 65 to 75 KIAS depending upon the amount of the
accumulation.
[12] Perform a landing in level attitude.

STATIC SOURCE BLOCKAGE

(Erroneous Instrument Reading Suspected)
[1] Alternate Static Source
Valve
[2] Airspeed
4 | 5 | 6 | SUPP |
--- PULL ON
--- Consult appropriate
calibration tables in Section 5
EMERGENCY PROCEDURES
PAGE 6