As we enter the winter season, now is a great opportunity to review engine operating procedures in cold weather. Matt Buckle at Airpart Supply Ltd. spoke with Chris Gayman, Supervisor of Product Support at Lycoming, to ask some questions about cold weather operations.
Matt: What maintenance items are important during cold weather operations?
Chris: At Lycoming Engines we emphasize customers should review and follow Service Instruction 1014 (Lubricating Oil Recommendations) and Service Instruction 1505 (Cold Weather Starting) before operating aircraft in cold weather conditions. (A comprehensive library of knowledge-based topics and service publications are available at Lycoming.com.)
To ensure the engine is easy to start, is it important to ensure that your ignition system is up-to-date on its maintenance. Spark plugs and magneto points should be properly gapped and ready to provide a strong spark. Poor condition of other systems such as induction, priming, exhaust and carburetor heat can influence the starting and operation of the engine, so those items should be inspected to ensure good condition and operation.
Ensure you are using the correct oil for the temperature range in which you will be operating. Using the incorrect oils can result in inadequate oiling directly after the engine is started and cause damage to your engine. Service Instruction 1014 provides guidance on what oils to use. The properties of multi-viscosity oils make it applicable across a much wider temperature range, and they may be advantageous to those pilots that are trying to escape the cold weather and head towards warmer climates.
Alternate air or carburetor heat systems should be inspected for proper operation.
Flight into snow or icing conditions can clog air inlets and air filters. If the alternate air system does not operate correctly, ice and snow build-up may starve an engine of air; this could reduce your available power or cause the engine to quit.
Batteries should not be overlooked. Freezing temperatures can destroy an aircraft battery. The battery with a full charge performs nicely, while one that is discharged will freeze. Once a battery freezes, the only remedy is to replace it. So it’s worth taking preventive measures. Should the battery run down during an attempt to start, do not leave it; get it charged immediately. Be certain that the master switch is always OFF while the aircraft is parked between flights.
Most importantly, you should have your heating system checked regularly. General Aviation aircraft tend to heat using one of two methods: a heat exchanger on the engine’s exhaust system, or a standalone combustion heater. Both options pose a risk of leaking Carbon Monoxide into the cabin, so these systems should be checked on their required interval (or earlier if you suspect an issue).
Chris Gayman, Supervisor of Product Support at Lycoming
Matt: When and how should I pre-heat my Lycoming engine?
Chris: For most Lycoming models, pre-heat should be applied anytime temperatures are at, or below 10°F. It is recommended that these guidelines be followed even when multi-viscosity oil is used.
In addition to hard-starting, not pre-heating the entire engine and oil supply system as recommended may result in minor amounts of abnormal wear to internal engine parts, and eventually lead to reduced engine performance and shortened TBO time.
Please note that engines should only be pre-heated a few hours or the evening before the intended flight, as preheating can have the side effect of moisture collection which can cause corrosion problems. Only heat your engine when you intend to fly it.
Multiple methods exist for pre-heating your engine. Options may include – but are not limited to – a heated oil sump pad, heated cylinder bands or probes, and warm air being pumped around the engine using a torpedo style heater. The use of a heated dipstick is not recommended by Lycoming, although most other methods are considered satisfactory. Permanently installed devices should follow all guidance provided by their manufacturers.
Matt: What items can I check during my pre-flight?
Chris: Look for fuel contamination before every flight by religiously draining fuel tanks and sumps. Water is one of the most likely contaminants of aviation gasoline. Flight into freezing temperatures makes any amount of moisture in the fuel system very critical. Even a tiny bubble of moisture may freeze in the fuel line and totally cut off the flow of fuel.
Once on board the aircraft, check the fuel-selector valve for freedom of movement. The fuel-selector valve can become frozen, and this is something you will want to identify while still on the ground.
If flight is planned into freezing temperatures, the preflight inspection should include observation of the relief opening in the engine breather tube. Moisture can freeze to the end of the breather and if the additional relief is blocked, it could result in a loss of engine oil.
If you can open your cowling, take the opportunity to inspect the exhaust system for signs of leaks. Leaks can be a source of carbon monoxide and should be corrected immediately before flying.
Matt: What considerations should I take when starting the engine?
Chris: First, follow the appropriate Pilot’s Operating Handbook for your aircraft. It provides the best recommendation for operation of your specific aircraft. Understand that the engine may be harder to start when it’s cold.
Although it is tempting to just keep grinding away with the starter to get it going, this is not recommended. If engine start has not occurred after three ten-second periods of operation with a pause between each, a five-minute period is required to cool the starter.
Take this opportunity to continue to pre-heat the engine while also taking yourself and your passengers inside to pre-heat with a hot chocolate. Using ground power can help provide an extra boost if the battery is weak and the starter is spinning the engine too slow.
About Airpart Supply Ltd.
Airpart Supply is a proud distributor for Lycoming Engines. Supplying Factory Engines and genuine spare parts to private owners, flying schools, FBOs and high-quality engine overhaul shops.
A ‘myth’ about purchasing a Lycoming Factory engine is that there will be chargebacks once the core engine has been inspected at the factory. This cannot be further from the truth. In fact, so long as the like-model, operating core engine follows the policy outlined in Lycoming SL250A, there will be no penalties or chargebacks.
In fact, your eligible factory engine will be upgraded to Roller Tappet Technology at no extra cost.
More information from www.airpart.co.uk/page/lycoming-engines