Yesterday I made a new experience. During the aircraft inspection and while taxiing to the holding point it was snowing. But only light snow which doesnât stick to the surface. The aircraft was completely clean. While lining up and during departure it suddenly became a more intense snowing and the snow was wet. So as the temperature was around 0 degrees it was freezing and I realized it when beeing in climb and in clouds. Climbperformance was standard. Thanks of tks the leading edges have been clean, also the wing root.
So I decided to continue the flight. After a short while I was above clouds. And finally it was absolutly uneventful beside the minus 26 degrees which made it cold in the cockpit. What would you have done?
I tend to be sceptical of Flght into Known Icing certification for pistons so the questions I would ask myself apply to FIKI and non FIKI.
Are you low IFR and what is your plan B if you need to return to the departure airport? An MEP arguably has more options on take off alternates, but OEI and in moderate icing the radius of one hour OEI which defines a take off alternate is likely to be theoretical. Perhaps someone has experienced OEI in moderate icing to comment.
If the icing is in convective conditions how likely is it before you reach clear air? This is a question on vertical development, and turbulence/intensity.
If you were an AOC holder, would you be dispatching? This applies to whether you are or are not carrying passengers – someone will be affected if you have an accident.
Looking at the picture above, I ask myself how would boot deiced aircraft cope with this ice. TKS will eventually melt the ice on top of the wings but boots obviously can’t do anything except keeping leading edge clean. Can anyone with boots experience comment?
No definitive or correct answer as no two flights and atmospheric conditions are the same. It worked out this time. It might not work next time. My subjective answer looking at your photo: if anything sticks to the wing before you are airborne cancel take off, taxi back and get anti icing. Supercooled water droplets can bring down the big guys, let alone piston singles.
Anti icing is expensive (airport ramper comes with a handpump and sprays it on), but worth it.
Concerning boots they will not help to keep the top clean and I can only speak for high performance turboprops. These guys will only be exposed to these conditions for a very short time during climbout. Higher airspeeds keep stuff from landing on the wing, boots keep the edge clear and later on no moisture at the flightlevels will help to keep the wing clean. Most importantly: they will be de/anti -iced with sticky fluid before departure if precipitation and icing conditions are prevailing to keep stuff from landing and staying on top of the wing as shown in the picture. Fresh warm fuel helps too.
