Cold Engine Starts
Even in California it can get cold enough to cold-soak an engine.
Long-layoff Start
A cold start stresses the engine, the starter, and the battery. Engines and their accessories should be preheated below 20-degrees F. You control only the fuel/air mixture. Only atomized fuel can be made explosive. Cold fuel does not evaporate as well as warm fuel so more time is needed to create the starting mixture. Pre-oil if you can by gaining access to interior of engine through an accessory port. Otherwise, pull the plugs and spray an oil mist into cylinders. (Use Marvel Mystery Oil) Now turn by hand to get oil pressure. After starting fly for at least an hour to make sure all moisture is burned out.
Turn the cold engine over a couple of times with the fuel off to clear the induction system. Next use the primer to put fuel into the induction system. This pump has jets that spray fuel into the intake manifold. Do not pump the throttle since pumping the throttle squirts a stream of gas upwards only to drip back down. This fuel can drip down and cause a engine fire if ignited by a backfire.
A cold start begins with two to three pumps of the primer. Lock the primer. Wait two to three minutes to allow the cold fuel to vaporize. As you begin to turn over the engine give a quick pump of the throttle.
If your engine does not have a throttle accelerator pump, you should leave the primer unlocked and fully extended ready to pump. Pull the throttle all the way out to 'choke' the engine. As soon as you turn over the engine give the primer pump a quick shot to enrich the mixture and lock it.
Pre Heat
You can use two 100 watt trouble lights inserted up through the cowl flap. This arrangement can give you > about a 40-degree temperature rise (use caution that the lights cannot break or damage any wiring or oil and fuel lines). Regardless of the system you use always pre-heat with an engine cowl blanket installed, this helps keep the heat around the engine." For the specifics on a cowling blanket, engine and cowling covers, you'll find all the information on the Cessna Pilots Association (CPA) web site under the Sources For... S-07, "Preheaters".
Oil Analysis
Howard Fenton at Engine Oil Analysis, 7820 S. 70th E. Avenue; Tulsa, OK 74133-7805.
Cold Weather Flying
Cold checklist
1. Have a new CO patch in the cockpit
2. Confirm with your mechanic that the muffler is o.k.
3. Winterize your engine and pre-heat your start (Drill out breather tube)
4. Provide for cockpit survival. with survival clothing
5. Check static and pitot for ice
6. Make sure quick-drains drain
7. Consider warming battery
8. Remove ALL ice, snow and frost.
Defrosting
Use a garbage bag filled with 10 or so gallons of hot water, knot the top and then wipe the top of the frost. This melts the frost and polishes it. As it re-freezes, the airfoil shape is maintained. Usually end up using 4 or 5 refills, and couple new bags, takes about 10 to 15 minutes.
Cold Flight Checklist
1. Only fly into improving weather
2. Know where to go to escape
3. Keep alternatives available
4. Runway lengths, surface and widths become critical
Preflight
1. Because of the cold the cold weather pilot tends to abbreviate the preflight. Don't!
2. Look for fuel dye as indicative of fuel leaks.
3. Keeping the tanks full keeps out moisture.
4. Ice in fuel looks like floating dust.
5. Check engine cylinders and exhaust fittings for white stains.
6. Prime 50% more than normal when it's cold and 100% if really cold.
7. Use manufacturer's recommendations for cold weather operations
8. If heat baffles are used check their security. Is a baffle called for over the oil cooler?
9. Let engine warm up until oil thins out and pressure is normal.
10. Crankcase breather hose and system must be free of moisture.
11. Hoses, flexible tubing and seals become brittle in cold
12. Battery and charging system should be in good condition
13. A cold battery will be weakened unless fully charged
14. Cold oil will be more viscous (thick)
15. Control cables' lubricants will congeal. Check throttle and CH.
16. Don't use anything that works on an automobile to remove ice
17. Deicing fluids cause corrosion and leave unpleasant residue
18. Keep fuel tanks full and protect against contamination. Super-cooled fuel can create ice crystals and a rough engine. C.H. helps.
19. Preheat engine and cockpit prior to start when 10-degrees F. Heat under constant attendance and not directly on surfaces.
20. Store in heated hanger until just before departure
21. Don't let water get on hinges or movable parts.
22. Clean and dry pitot tubes, heater intake, carburetor intake, control surfaces and wheels.
23. Melt ice and remove all moisture, which may freeze again. Use hot water bottles or double-bagged plastic bags and plenty of dry towels
24. Check weep-holes under aircraft and drain interior moisture.
25. Confirm fuel selector is not frozen in one position.
26. CO detectors are recommended in addition to heater inspection
Operations
1. Thirty seconds of cranking = 50 hours flight time wear
2. Phone your destination just prior to departure
3. Plan to walk home.
4. Electrical loads will be heavier.
5. Don't set parking brakes, hot brakes will freeze solid.
6. Idle at higher rpm to keep plugs from fouling and oil hot
7. Normal engine temperatures are required to evaporate moisture in crankcase.
8. Change tanks more often so that maximum fuel is available. Fuel selector might freeze.
9. Flooded? Mixture out, throttle full. Crank 20 seconds.
10. Fuel/air more reluctant to ignite. Carburetor heat may be required for takeoff
11. Don't use throttle to over prime (two strokes maximum). Use engine primer, not throttle.
12. Most common cause of aircraft engine fires is prime with throttle
13. Prime only with primer. Over priming can be harmful.
14. If RPM rises when carburetor heat is applied it means that air filter is blocked
15. Don't try to force the warm-up
16. Gyros will need to warm up and speed up, too
17. Control cables will be tighter and stiff
18. Don't hand prop.
19. Keep wheels and brakes as dry as possible
20. May need to remove and dry plugs if engine fires only briefly.
21. Use radios only after electrical system has run a few minutes.
22. Braking may be poor to nil
23. Oil must be hot to perform properly. More viscous (thick) oil requires more cranking energy
24. Fix problems early before they become 'unfixable'.
25. Consider landing gear up
26. Use C. H. in icing range
27. Use C. H on approach and descent
28. Keep power up during descents and extend any drag that may be available. This will keep the engine warmer.
29. Taxi slowly, wheel bearings may be frozen, brakes may not hold.
30 Don't use flaps if tailplane icing is at all likely.
31. Don't use brakes until tires are on hard surface. Be prepared for ineffective braking. Touchdown areas of runways are more slippery.
Performance
1. Performance on runway may be less.
2. Reduce crosswind capability by 50% for snow and 75% for ice
3. On getting airframe ice, change altitude.
4. Climb through ice at high speed and shallow angle.
5. Descend through ice at lower speed but high rate of descent.
6. Climb above wet snow and freezing rain.
7. Reduced windshield transparency makes surfaces appear lower than they are. 5-degree slope errors are common.
8. If your planned altitude is within 4000' of z-level anticipate ice.
9. Plan an alternate route around convective weather.
10. Know the "times" as they apply to your flight. (fuel, battery, speed, alternate, etc)
11. Set power at cruise and don't change anything. Thus, if anything changes it means there is a change in power. Suspect carburetor or induction icing.
Conditions
1. Ramp operations can cause 'black ice' problems for taxiing.
2. Weather systems move more quickly in winter. Fast-moving winter systems create turbulence and hazardous conditions.
3. Just because no ice is forecast doesn't mean there won't be any.
4. If you are flying in air only 10 degrees above z-level anticipate ice.
5. Freezing weather can make a survivable problem non-survivable
6. Where is the good weather?
7. Expect strong winds from the wrong direction
8. Snow changes the way things look
9. Light icing over a time is a serious problem
10. Ice usually exists under snow.
11. Moisture on runway that gets on aircraft may freeze when airborne.
12. Clouds dropping rain have less ice potential than do those without rain.
13. Top portions of clouds contain supercooled droplets.
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