This is the second installment of a seven-part series “TKS – A Clear Solution to Icing,” by Jeffrey Brewer, CEO/Founder of Connecting Aviators.
It makes sense that an aircraft builder based in Minnesota wouldn’t just slip up on the idea of ice protection. For decades, Cirrus airplanes have flown with an ever-evolving clear solution for ice.
The TKS solution centers on weeping titanium panels added to the leading-edge flight surfaces. The panels are laser perforated with 800 tiny holes per square inch. A porous membrane behind the panels assists with even fluid distribution. On the propeller hub, a slinger ring with a port on each blade releases ethylene glycol fluid that flows over the propeller then back onto the fuselage and windshield.
In 2002, inadvertent ice protection was introduced on the first-generation Cirrus SR22. The same design continued forward on Generation Two planes. But by 2007, the Generation Three SR22 sported a re-engineered wing and was released with noteworthy TKS enhancements.
For those unfamiliar with Cirrus planes, the initial G1, G2 and G3 TKS systems are not certified for flight into forecasted or known ice. It’s an inadvertent “no hazard” system for normal operations only. No certified determination has been made for its capability to prevent or remove ice accumulation.
In 2009, Cirrus and CAV Ice Protection announced a FIKI-certified system that has additional features and upgraded components over the previous inadvertent ice protection option. The FIKI system was a clean-sheet redesign that increased fluid availability, flow rates, distribution and equipment reliability.
Jerry Jordan, CAV Ice Protection VP of Design Engineering said, “The Cirrus Flight Test group performed 33 natural ice flight tests with the FIKI system. Of those, 30 provided extensive encounters in icing conditions, which produced some great real-world data on the system’s operation.” Cirrus states, its “Known Ice Protection is an actual FAA re-certification of the SR22 plane to permit pilots to legally fly into known icing conditions.”
Both FIKI and inadvertent anti-icing systems use an ethylene glycol-based liquid, called TKS, that shifts the freezing temperature of water to minus 76° F (-60° C). When supercooled water in the cloud mixes with TKS, the freezing point is depressed below ambient temperature and allows the combined mixture to flow off the aircraft without freezing.
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