Page 8 - Jan24T

Let’s start with some icing basics. High-performance business jets perform optimally with smooth, uninter- rupted airflow over their wings, tail and control surfaces. Introduce some disturbance to the airflow, and that op- timization quickly erodes. Studies have shown that icing only as thick and rough as sandpaper can reduce lift by up to 30% and increase drag even more - as much as 100%. That eye-watering fact should make any aviator understand that icing is serious business, regardless of the aircraft flown.
As with most risk management, the best way to mini- mize negative consequences is to identify and mitigate the most significant dangers. This risk mitigation is es- sential for cold weather operations. In a perfect world, we would operate in calm, clear conditions and preferably to a destination near fine sand, warm water and delicious foods grilled on a stick. The reality is that we must attend meetings, visit loved ones or deliver goods to places that don’t fit my description of a perfect world – and we will be flying into icing conditions. Heck, your perfect world may be fine powdered snow while gliding down the ski slopes. Anyone operating in an icing environment must do their homework and master many things, including recognizing the conditions conducive to icing, deicing/ anti-icing systems of their aircraft and the procedures each manufacturer recommends.
Detailed knowledge of meteorology beyond the ba- sics is essential. A thorough understanding of frontal
characteristics, temperature inversions, types of icing, and accumulation rates is critical – not optional. Knowing what goes into Icing Forecasts, AIRMETS, SIGMETS, field condition and braking action reports will give a disciplined pilot the information needed to make safe operational decisions.
FAA Advisory Circular 91-74B, titled Pilot Guide: Flight In Icing Conditions, is an invaluable resource that concisely (in 63 pages no less) covers everything any pilot should consider before attempting to operate in cold weather conditions. If one adopts a practice of periodic review, AC 91-74B is a valuable document to put on the list.
One of this AC’s many topics is explaining certification requirements and how they have changed over time. Be- fore 1973, Part 23 aircraft were certified for light icing and flight into moderate icing for a limited time only. Those pre-’73 ice protection systems can only be considered a means of escaping an icing condition. It’s vital for anyone flying one of these aircraft to understand and respect this limitation. There are too many cases of overconfident pilots flying into icing conditions with the false impres- sion that their aircraft could handle these conditions, often to their peril.
As time passed, certification included testing for flight into known icing (FIKI). Just because your aircraft may be certified FIKI, this is no magic bullet that allows you to disregard proper planning and decision-making.
6 • TWIN & TURBINE / January 2024