Ice is the last great unknown in instrument flight — although wide areas of suspected icing conditions may be forecast, there is *no* technology that can tell you specifically where you’ll encounter ice. This leaves us with two basic choices:
- Don’t fly in the clouds at all when conditions are near or below freezing; or
- Gamble on the fleetingness of icing conditions … and luck.
Whatever you do, remember: You are responsible for the decisions you make and FAA enforcement and case law trends toward ‘criminalization’ of any flight anywhere near actual or forecast icing conditions in an airplane not certified for flight in ice.
THE COMPROMISE between grounding your airplane all winter and haphazardly launching into ice-laden skies is to adopt — and stick to — a few standard operating procedures that dramatically increase you airplane’s wintertime utility, but avoid the greatest threat of ice.
RULES FOR SAFER ICE FLYING
- INSPECT THE WEATHER: Study the TAFs, Area Forecasts, Constant Pressure Charts, and PIREPs. Look for ‘clear zones’ between layers of clouds, and fly at those altitudes. Always be sure you can get down without traversing icing conditions or don’t go…
- CHANGE PLANS: You will have to delay or cancel some flights for ice — accept it, do it.
- ESCAPE: A trace of ice on the windshield means it’s time to find warmer air, now.
Its OK to Fly:
- When there is at least 3000 feet of ice-free air (cloudless sky, or temperatures above freezing) above the surface — ALWAYS have warm air below you.
- When you know the direction (horizontally and vertically) toward clear or above-freezing conditions and you are ready to deviate at any time.
DO NOT FLY:
- In stratus clouds and precipitation at altitudes with temperatures from 0C to -15C.
- In cumulus clouds and precipitation at altitudes with temperatures from 0C to -40C.
- Over broken or overcast cloud layers that are in the icing temperature range.
BOTTOM LINE: Approach winter IFR flying with great care and caution and you won’t have to completely give up the airplane’s utility during the cold months.