This is the fifth 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.
Known Ice Protection FIKI, Cirrus SR22 G3-G6 (2009 & later)
By 2009, Cirrus and CAV Ice Protection had designed a system to meet certification requirements for Flight Into Known Icing. The FIKI system has upgraded components, redundancy and new features.
The titanium panels can thoroughly and evenly coat all critical flight surfaces and flow more fluid. Cirrus added mini titanium panel “horns” to the elevator mass balance to reduce the risk of ice bridging. And the vertical stabilizer front edge was given a fluid panel. Ice accretion can change a plane’s angle of attack, so a heated stall vane and angle of attack sensor were added to the leading wing edge and a high-heat-capacity pitot tube. Dual OATs were added on the G6.
At night, split-prism LED lights illuminate both wings and horizontal stabilizer surfaces. And the onboard EVS infrared-plus-visible spectrum sensor camera can help pilots see and avoid clouds after sunset.
The FIKI system has capacity to carry more fluid. Each wing has a 4-gallon fluid reservoir for a total capacity of 8.0 gallons. Pumps automatically cycle between each tank to keep levels roughly even and reduce pilot workload. Three pumps provide fail-safe redundancy.
As with the basic TKS ice protection, a slinger ring protects the prop blades. Some fluid slung from the prop will flow onto the fuselage and windshield, but the FIKI system includes a windshield spray nozzle to help safeguard pilot forward visibility. The windshield pump can also be used to prime the system if air gets trapped in the lines from running the tanks dry.
The pilot can select between three pump rates: normal, high and maximum. In normal mode, full tanks allow an operating time up to 150 minutes. In high mode, operating time is up to 75 minutes. With repeated maximum mode usage, expect an operating time of less than 37 minutes.The FIKI system provides full operating envelop protection. Maximum anti-ice performance is available with airspeeds between 95 KIAS (best climb angle) and 177 KIAS at any altitude, but not to exceed 204 KTAS. When the TKS system is turned on, Cirrus Perspective by Garmin monitors the airspeed. If the airspeed drops too low or exceeds upper limits, the CAS will notify the pilot.
Pilot critical decision-making is supported with real-time info from Cirrus Perspective by Garmin, including 1) Amount of TKS fluid in each tank, 2) Nautical range remaining for flow rate selected, 3) Available anti-icing time for each flow rate (normal, high or maximum), 4) Alerts to inadequate system pressure or malfunctions, and 5) Icing forecasts and freezing areas with SiriusXM datalink weather.
The FIKI system added about 61 pounds of weight without TKS fluid, or 23 pounds more than the basic ice protection. The additional weight depends on how much fluid you’re carrying. Two full reservoirs add 73 pounds for a total system weight of 134 pounds (73 + 61 = 134 lbs). TKS weighs 9.125 pounds per gallon.
In 2009, the plane’s empty weight decreased by using a new Hartzell propeller with a lighter hub as standard equipment. The forward weight reduction allowed for the removal of a tail ballast. This design change offset the incremental weight of the known ice protection system without fluid. In 2013, Cirrus innovated again with another re-engineered wing and numerous changes that certified the Generation Five SR22 for an extra 200-pound increase in useful load.
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