TKS Technology Offers Method To Meet New Icing Regulations

Cav Ice Protection, which manufactures the TKS ice-protection system, has developed a new method of leveraging TKS technology to help aircraft manufacturers meet new FAA flight into known icing (FIKI) requirements for freezing rain and supercooled large droplet (SLD) icing. Its new SLD Guard system adds TKS strips in vulnerable areas such as upper wing surfaces in front of ailerons and upper and lower horizontal stabilizer surfaces.

The strips are less than an inch wide and laser drilled with thousands of .0025-inch holes—just like TKS’s leading-edge panels—through which an ethylene-glycol fluid is pumped. The fluid, with a freezing point lower than -70 degrees F, disperses over the flying surface and acts to de-ice and prevent ice from forming (anti-ice), according to Cav. 

The new FAA rules apply to certification programs that begin after the regulations took effect Jan. 5, 2015, and apply to transport-category aircraft weighing less than 60,000 pounds or those with reversible flight controls (direct mechanical connection between the control surface and yoke). The newly revised Part 23 regulations also address SLD requirements, specifying either a means of detecting SLD and allowing an escape from SLD conditions or equipment that allows the airplane to fly safely in SLD conditions.

“SLD Guard provides anti-ice and de-ice protection from SLD conditions, as specified in the FAA regulations,” said Cav v-p of design engineering Jerry Jordan. “Specifically, the system is designed for encounters with severe freezing rain and freezing drizzle, as defined in Appendix O of the new regulations, allowing the aircraft to safely exit these dangerous icing conditions. SLD Guard now permits aircraft to be certified for continuous operation in all…section 25.1420 Appendix C and Appendix O conditions.”

According to Cav, SLD Guard offers benefits for existing designs and is retrofittable to aircraft with all types of existing ice-protection systems such as pneumatic boots, thermal, expulsive and freezing-point depressant such as Cav's TKS. SLD Guard can also be fitted to new aircraft already equipped with these ice-protection systems, “regardless of the primary ice-protection system technology selected by the manufacturer,” according to Cav. The company said that it “is currently working with aircraft manufacturers to incorporate SLD Guard into new aircraft programs.”