Cessna 172R Skyhawk — Mark_Munn_Chopperline_Flight_Training_Checklist_C172R_Emergencies

Inadvertent Icing Encounter Inadvertent Icing Encounter

• Turn Pitot heat SwitchON
• Turn back or change altitude to obtain an outside air temperature that is less conducive to icing.
• Pull cabin heat control full out & open defroster outlets to obtain maximum windshield defroster airflow. Adjust cabin air control to get maximum defroster heat & airflow.
• Watch for signs of engine-related icing conditions. An unexplained loss in engine speed could be caused by ice blocking the air intake filter or, in extremely rare instances, ice completely blocking the fuel injection air reference tubes. Change the throttle position to obtain maximum RPM. This may require either advancing or retarding the throttle, dependent on where ice has accumulated in the system. Adjust mixture, as required, for maximum RPM.
• Plan a landing at the nearest airport. With an extremely rapid ice build up, select a suitable “off airport” landing site.
• With an ice accumulation of ¼ inch or more on the wing leading edges, be prepared for significantly higher stall speed and a longer landing roll.
• 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.
• Open left window and, if practical, scrape ice from the portion of the windshield for visibility in the landing approach.
• Perform a landing approach using a forward slip, if necessary, for improved visibility.
• Approach at 65 to 75 KIAS depending upon the amount of the accumulation.
• Perform a landing in level attitude.

Static Source Blockage Static Source Blockage

Erroneous Instrument Reading Suspected

• Static Pressure Alternate Source ValvePULL ON
• AirspeedCONSULT APPROPRIATE CALIBRATED TABLES IN SECTION 5 POH

Ammeter shows EXCESSIVE RATE OF CHARGE (Full Scale Deflection) Electrical Power Supply System Malfunctions

Ammeter shows excessive rate of charge (full scale deflection)

• AlternatorOFF
• CAUTIONWith the alternator side of the master switch off, Compass deviations of as much as 25 may occur.
• Non essential Electrical EquipmentOFF
• FlightTERMINATE AS SOON AS PRACTICAL

Low Voltage Annunciator (volts) ILLUMINATES DURING FLIGHT Low Voltage Annunciator (volts) ILLUMINATES DURING FLIGHT (Ammeter Indicates Discharge)

Ammeter indicates discharge

• NOTEIllumination of “VOLTS” on the annunciator panel may occur during low RPM conditions with an electrical load on the system such as during a low RPM taxi. Under theses conditions, the annunciator will go out at higher RPM. The master switch need not be recycled since an overvoltage condition has not occurred to deactivate the alternator system.
• Avionics Master SwitchOFF
• Alternator Circuit Breaker (ALT FLD)CHECKED IN
• Master SwitchOFF (BOTH SIDES)
• Master SwitchON
• Low Voltage Annunciator (VOLTS)CHECK OFF
• Avionics Master SwitchON
• If low voltage annunciator (VOLTS) illuminates again:
• AlternatorOFF
• Non essential Radio & Electrical EquipmentOFF
• FlightTERMINATE AS SOON AS PRACTICAL

Vacuum System Failure Vacuum System Failure

Left Vacuum (L VAC) Annunciator illuminates or Right Vacuum (R VAC) Annunciator illuminates

• CAUTIONIf Vacuum is not within normal operating limits, a failure has occurred in the vacuum system and partial panel procedures may be required for continued flight.
• Vacuum GaugeCHECK
• NOTEto ensure vacuum within normal operating limits