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landing gear “Squat switches” (also known as a WOW switch; Weight On Wheels). Not until the airplane lifts off does the circuit allow operation. It cannot be tested on the ground.
Every time the lower, forward cowling is removed for maintenance, the wiring to the Lip Boot must be disconnected. A quick-disconnect fitting is installed to make the job easier. Obviously, it is important that the disconnect be hooked back up correctly when the cowling is reinstalled. The mechanic, however, cannot verify operation on the ground. As the pilot, remember to turn on the Lip Boot heat switches when airborne on the first flight after maintenance. Then verify that each side, individually, causes a rise on the loadmeters – each boot pulls about 20 amps. The 100 and A100 models have a switch labeled Left and Right (although it operates Up and Down) that allows getting an actual readout of the current going to the respective lip boot. Instead of adding another dedicated ammeter gauge in the cockpit, however, they “Rob Peter to Pay Paul” and use the Prop Heat ammeter instead. The meter’s face is marked with separate green arcs for Prop and Lip Boot current, one on top of the meter’s white arc line and one on the bottom. Similarly, the F90 model has a voltmeter/ammeter selector position that allows lip boot current to be read on the overhead ammeter.
Probably more important than any other ice protection item are the engine Ice Vanes. I referred briefly to these when I stated that some models had four instead of two Ice Protection switches on the pilot’s left, not right, subpanel: Engine Anti-Ice. That is the “modern” name for ice vanes. No King Air is still in production that requires or allows manual Ice Vane operation. Yet from the mid-A90 production up through the B90, C90, C90-1 E90, F90, 100, and A100 the ice vanes were operated manually. T-handles are located beneath the pilot’s subpanel. When pulled, they extend the ice vane (there was only one movable part per side for many years, no bypass door existed) and an over-center action locked it in the extended, down position.
I used the following “laugh line” hundreds of times in the old days: “You can tell a new King Air pilot from the blood on his knuckles. You can tell a high-time King Air pilot by the fact his fingers are shorter than most.”
The “blood on the knuckles” comes from having difficulty in pushing hard enough to get the ice vane linkage to break back to the other side of center. In frustration, the pilot makes the big no-no of pushing harder on the T-handle while having his palm facing to the floor, not up to the overhead. Suddenly the mechanism releases, the handle slams forward, and a
SEPTEMBER 2021
KING AIR MAGAZINE • 21