Page 24 - Volume 15 Number 9

layer of skin from the pilot’s knuckles is now decorating the bottom metal edge of the subpanel. Ouch! Palm up is the only way to go!
(As for the shorter fingers? That follows all of the tapping we must do to get proper readings ... on fuel gauges, loadmeters, prop ammeters, etc. Why are you nodding in agreement?!)
I have written entire articles in the past concerning the criticality of ice vane usage. Yes, many pilots have not yet been convinced of their importance and they are reluctant to extend them until ice starts forming on the wing. But I believe strongly that technique is misguided and is asking for an expensive repair to the ice-damaged PT6 compressor. I’m a lucky guy but I won’t tempt fate when it comes to engine ice vanes. “When in doubt, get ‘em out!”
Let’s review and count the various anti-ice protection items on your King Air:
= Auto-Ignition switches
= Engine Anti-Ice switches or Ice Vane handles 2
= Prop Heat switch 1 (at a time) = Lip Boot Heat switches (if installed) 2
This adds up to a total number of switches/handles ranging from 10 to 13, depending on the exact King Air model. In fact, some early long-range navigators included a heated probe as part of their air data system and a switch was placed on the pilot’s left subpanel labeled “Probe Heat.” Including that one, our count can reach 14.
“Wait a minute, Tom! You left out a couple that are on my King Air. I have left and right Fuel Control Heat switches, too.”
Of course, you are correct. Incorrectly, many pilots think these switches heat fuel. No, they’re not Fuel Heat switches but are Fuel Control Heat switches. They send current to heat the P3 air being supplied to the Honeywell (nee Bendix) Fuel Control Unit (FCU). Originally, the Beechcraft and Pratt & Whitney engineers believed that obstructing this line with ice would only be a possibility when flying in cold visible moisture. Hence, they located the switches on the pilot’s right subpanel right along with all of the other ice protection switches. However, it was found that, somewhat akin to carburetor ice, the blockage could occur even in clear air. When this occurred, the engine would lose all useful power as the fuel flow rolled back to Minimum Flow. Not good! The POM/POH procedure was
= Pitot Heat switch
= Fuel Vent Heat switch
= Stall Warning Heat switch (if installed) = Windshield Heat switch
2
2 2 (or none) 1 1 or 2
22 • KING AIR MAGAZINE
SEPTEMBER 2021