Cold Weather Ramp Operations: NOTE: All temperatures referred to below are reported ground temperatures. Preheating & External Power Source: Preheating and use of an external power source is recommended when air temperatures are below 20°F. Preheating is required when air temperatures are below 10°F, for the first flight of the day and thereafter if its been two hours since the last flight. Notify line service when preheat or external power source is needed. The winterization kits are not to be installed during preheating. Deicing: Absolutely no ice scrapers will be used on UCM aircraft. Use the soft bristle broom on metal surfaces only to remove snow. Rub windshield with soft rags only in a vertical motion. Winter Kits - Install and remove winter kits according to the following: From 30°F/-1°C and above – Winter Kits OFF From 20°F/-7°C and below – Winter Kits ON Between 20°F/-7°C and 30°F/-1°C – If the winter kits are on, leave them on If the winter kits are off, leave them off
The winterization kit consists of two cover plates (nosecap covers), with placards, which attach to the air intakes in the cowling nosecap (Cessna C172SP PIM). Pilots are allowed to install and remove winterization kits, maintenance or line service personnel are not required. Winter Kit OFFWinter Kit ONWinter Kit
How to Install: The Winter Kits (nosecap covers) are located in the baggage compartments of the Cessna 172R and C172S models. Youll need a Philips head screwdriver for installation
Installation Steps: Step 1:Remove the four screws which are located on the cowling near the propeller spinner. Step 2:Place the Nosecap Cover (Winter Kit). Using the screws you just removed, screw the Nosecap Cover (Winter Kit) in place. Step 3:Repeat the process for the Nosecap Cover (Winter Kit) for the opposite air intake. Step 1 Steps 2 & 3
Prior to Start: Aircraft NOT Preheated: Prior to starting turn the propeller manually through several engine compression cycles by hand to loosen the oil, so the engine cranks more easily and uses less battery power. NOTE: The Master Switch should be OFF. The ignition should be in the OFF position. The Keys should be removed and the propeller should be rotated opposite the direction of normal rotation. NOTE: During cold weather starting, when performing the Standby Battery energy level test, the test lamp may not illuminate and the BUS E volts may be less than 24 volts before turning on the MASTER (ALT and BAT) switch. After engine start, verify the S BATT ammeter shows a charge (positive) at 1000 RPM or greater. Prior to takeoff verify the S BATT ammeter shows a charge less than 0.4 amps. Aircraft Preheated: Operations as normal. Starting: Cold weather starting procedures are the same as normal starting procedures. Starting Problems: If the engine does not start during the first few attempts, or if engine firing diminishes in strength, the spark plugs may be frosted over. Preheat must be used before another start is attempted. Starter Limitations: Crank the starter for 10 seconds followed by a 20 second cool down period. This cycle can be repeated two additional times, followed by a ten minute cool down period before resuming cranking. After cool down, crank the starter again, three cycles of 10 seconds followed by 20 seconds of cool down. If the engine still fails to start, an investigation to determine the cause should be initiated. C172S Only
Post-Start & Taxi: Aircraft Preheated: Taxi operations are the same as normal taxi operations. Aircraft NOT Preheated: During cold weather operations, the oil temperature indicator may not be in the green band prior to takeoff if outside air temperatures are very cold. Allow for a suitable warm-up period after starting (2 to 5 minutes at 1000 RPM). During taxi, do not exceed 1300 RPM for a period of 10 minutes after engine start. After a suitable warm-up period, accelerate the engine several times to higher engine RPMs. The airplane is ready for takeoff if the engine accelerates smoothly and the oil pressure remains normal and steady.
Cold Weather Maneuver Limitations: All temperatures listed below are surface temperatures. Operating at low power settings during cold temperatures is limited as follows: From 20°F/-7°C to 15°F/-12°C Normal operation. Monitor cylinder head temperatures (if equipped), exhaust gas temperatures, and oil temperatures for proper operational limits. Maintain in-flight power settings at or above 1500 RPM or 15 MAP. – From 15°F/-9°C to 10°F/-12°C Cruise maneuvers only. Solo flights are authorized for students that demonstrate satisfactory knowledge and skill regarding cold weather operations. Monitor cylinder head temperatures (if equipped), exhaust gas temperatures, and oil temperatures for proper operational limits. – From 10°F/-12°C to 0°F/-18°C Dual flights only. Cruise maneuvers only. Monitor cylinder head temperatures (if equipped), exhaust gas temperatures, and oil temperatures for proper operational limits. – From 0°F/-18°C Flight operations cease. Due to the possibility of thermal shock: – All power changes at cold temperatures should be made smoothly. – Abrupt power changes will not be made. – Keep fuel air mixture leaned out during descent. – Monitor and maintain the greatest possible engine heat for the power setting selected below 20°F/-7°C. – Power off conditions can be simulated at full flaps and 1500 – 1700 RPM during cold temperatures.
When to Preheat: Preheating recommended below 20°F. Preheating required when below 10°F, or two hours since the last flight. Ensure winterization kits are not installed during preheating. Winter Kits - Install and remove winter kits according to the following: From 30°F/-1°C and above – Winter Kits OFF From 20°F/-7°C and below – Winter Kits ON Between 20°F/-7°C and 30°F/-1°C – If the winter kits are on, leave them on If the winter kits are off, leave them off Starting: Aircraft Preheated: Operations as normal. Aircraft NOT Preheated: Rotate the propeller opposite the direction of rotation a for a few cycles to loosen the oil. Make sure the Master is OFF, the Ignition is OFF and the Keys are out. Post Start and Taxi: Aircraft Preheated: Start as normal. Aircraft NOT Preheated: Warm-up period 2-5 minutes at 1000 RPM During taxi, do not exceed 1300 RPM until 10 minutes have passed since engine start.