If you live in sunny southern California do you really have to worry about cold weather flying? The answer is, “You bet your sweet bippy.”
With our mild climate we can be lured into a false idea that we don’t have to check and plan for cold weather like someone in Fargo, North Dakota. Truth is, airplanes are meant to go places so if you want to go to Big Bear or Mammoth to go skiing this winter you need to pay attention to the rigors of flying in cold weather, particularly if you have an instrument rating.
It’s not uncommon for the freezing level to drop below 6,000 feet MSL here in San Diego County and that’s one of the preferred altitudes for many of the tower en-route IFR clearances in SoCal. Add a winter stratus layer of clouds at or above the freezing level and you have the instant potential for airframe icing.
Even with clear and a million VFR weather at any of the airports serving your favorite ski area you will still have to be familiar with your airplane’s cold weather starting and operating procedures. You may want to pre-heat the engine or oil before starting. However, the major ingredient for a successful ski weekend is snow so, you have to be hoping for fresh powder which will alter your pre-flight preparations for the trip home if you don’t hangar the airplane which actually isn’t a bad option if you expect snow or freezing rain while you are there. De-icing an airplane in clear weather can present challenges and it can be expensive. You must use an FAA approved de-icing fluid and no automotive anti-freeze products qualify. If you can wait for the sun to get rid of ice, snow or frost you’ll save some money but, make sure there’s no residual moisture in any of the flight control mechanisms that can re-freeze when you climb into colder air. The accompanying photo is a San Diego based plane on a Christmas trip to Sunriver, Oregon. This pilot got the airplane into a heated hangar to get rid of the ice and snow.
Another problem for those of us who fly airplanes that are not approved for flight in known icing is planning a route to avoid areas of known icing or make the decision to delay the flight until conditions improve. A really useful planning tool is the Java Flight Path Tool on the NOAA Aviation Weather Center website at http://www.aviationweather.gov. You get to it by clicking on “Icing” under “Forecasts” on the left side rail of the home page and then clicking on the “Flight Path Tool” link in the middle of the icing page. This program lets you plot your route of flight and then gives you a plan view and a profile view of the flight path with forecast icing conditions both laterally and vertically so you can plan to avoid them by going around, under or over the forecast areas depending on your aircraft’s performance and the terrain. The most important thing to remember about is tool is that it is a FORECAST which is really nothing more than an educated guess that may or may not be right so give yourself a big (conservative) margin of error and closely monitor your actual in-flight conditions for visible moisture above the freezing level.
A nice thing about winter weather in San Diego is that you get the opportunity to fly real instrument approaches with well defined ceilings. All you have to do is pick an overcast day with a ceiling you feel comfortable with when the freezing level is sufficiently high as to not be a problem.
Enjoy the winter weather and fly wisely.