I once flew with a CFI who pointed to a switch in the cockpit and said, “That’s a ‘dusty switch.’” I pondered that comment and then had to ask, “What’s a dusty switch?” He told me that a dusty switch is “a switch that is hardly ever touched, or a switch that you should not touch on a regular basis.” I grinned and thought some more. Since then, I have used the phrase “dusty switch” many times in training.
He was right, there are dusty switches in the cockpit. Some are dusty even though they should be touched more often and others are dusty because we’ve forgotten what they do and have allowed disuse to cloud our memory. The bottom line: Just because a switch is dusty does not mean it is not important. We must know what they do so we are prepared in case we do need them.
I recently had a long flight and decided to clean the cockpit by breaking out a container of disinfectant wipes. As I wiped each switch, I thought to myself, “I bet no one has touched that switch in years!” I decided to record which switches were truly “dusty switches” and share it with you.
Here’s my list of King Air switches that I bet are dusty in your King Air, too.
Fire Extinguisher Test switch
Are you really testing the fire system in your King Air? I bet not. I rarely see pilots check this system and maybe that’s not so bad. In my 25 years of flying King Airs, I’ve never heard of nor seen a fire in the trusty PT6 engine, on any airframe, let alone the King Air.
Could there be a fire in the engine compartment? Sure. But it is not a prevalent problem. In fact, in other airframes that have the same engine type found on King Airs (Piper M600/700, TBM, etc.), the fire detection system has been removed – simply because it caused more maintenance benefit than emergency identification benefit.
Is it worth checking the engine fire detection system? Sure. You should probably test this system on an upcoming flight. But this system is certainly one of the least understood and least used.
There are several different fire detection systems in the King Air fleet, but the most prevalent systems are those that have a DET and EXT test position on the switches. The DET checks the continuity of the detection loop and the EXT checks the continuity of the wiring to the squib and cartridge circuit.
When is the fire system tested unexpectedly? Mostly by DPEs on check rides! The fire system test switch is on the right side of the cockpit, within easy reach of a cunning DPE’s fingers. On a takeoff, I’ll occasionally turn ON the fire lights early on the takeoff roll, which makes a ton of visual noise. Red lights will come on the panel and the master caution lights will illuminate too. It should get your attention. Of course, the appropriate action early on that takeoff roll is to abort the takeoff when “any abnormal cockpit indications are present” prior to rotate speed.
This is a good time to remind yourself to conduct a takeoff brief, even if you are simply briefing only yourself. You should have a prepared plan for every takeoff that includes a plan for an engine failure before V1, after V1 and what the heading/course/altitude is to be flown. Even though engine failures are extremely rare in the King Air, they can be a dastardly affair if mishandled. A basic takeoff brief will remind you of those critical items that must be accomplished by memory, the action items that can save the day when the chips are down or when your DPE pulls a fast one on you.
Cabin/Cockpit Air knob
This knob is found on the copilot side of the airplane and is usually called the “rob knob.” If the copilot pulls this knob, the air that was going to the cabin area is now diverted (partially) to the cockpit. Effectively, the copilot can limit the amount of air that goes to the back of the airplane. You can feel the rush of air near your feet if you pull this knob. I pull this knob if I want to get a really good idea of the temperature of the air going to the back of the cabin, and then I’ll push it back in after checking.
But, what happens sometimes is that this knob is pulled on a previous flight, and the position of the knob is not noticed in subsequent flights when no one is sitting in the right front seat. The rob knob resides under the yoke and it is not easy to see unless you are intentional. This causes the air to be diverted to the front and it can cause your passengers to become cold.
This happened on a recent flight on a cold day where I pulled both “rob knobs” (there’s one on the pilot side too) to divert the heat to the front on a deadhead leg (no passengers). Then, when I loaded up the passengers they were in the back of the airplane wrapped in blankets until one of them told me how cold it was in the back, noticing I was warm and comfy in the front. I pushed those knobs back in and solved the problem.
CWS button
Most pilots have never pushed this button. Or, if they have, they usually don’t know what it does. CWS stands for control wheel steering, which is a poor name because you’d have no clue what this button does based on its name.
This button is related to the autopilot, and when pushed it will do two things:
- Release the pitch and roll trim servos, allowing the pilot to hand-fly the airplane. When the CWS switch is released, the pitch and roll servos are reengaged.
- Adjust the pitch mode of the autopilot to a new pitch reference.
If you have selected ALT (altitude) mode, then you can push the CWS button, hold it and hand-fly the airplane to a new altitude. When you release the CWS button, the autopilot will reference that new altitude. If in V/S (vertical speed) mode, when you push the CWS button, it will allow you to fly the airplane to a different vertical speed and when you release the CWS button, that new V/S will be referenced by the autopilot. When in pitch mode – you guessed it – you can push the CWS, fly the airplane to a new pitch attitude and then release the CWS button to have the autopilot reference that new pitch attitude. It’ll do the same if you are in airspeed mode. If the autopilot is ON, then a pitch mode is active and the CWS allows you to modify that pitch parameter while hand-flying.
When would you use this feature? If your autopilot is an older style (non-digital) and doesn’t level off at the exact altitude, you can use the CWS to make small changes easily. When using the TOGA (TakeOff/GoAround), you are putting your autopilot into pitch mode (usually 7.5 degrees). If on climb out you desire a different pitch attitude than the prescribed pitch attitude, it is easy to use the CWS to make a small change.
Basically, newbies to the King Air will not use the CWS. It’s just too complicated and pilots migrate to just ignoring its features or were never taught the CWS in initial training. But you’ll observe a seasoned veteran use the CWS in certain phases of flight, and using it puts the airplane in a better position. It is a nuanced button that is often dusty. Now that you know more, maybe you can give this button a try on a future flight. You might just find that it is helpful!
Window Defog knob
I remember flying an airplane from Florida to Colombia (a super-humid part of the world) and flying at high altitude to take advantage of the lower fuel burn. Of course, it was bitter cold at high altitude. Then, ATC delayed my descent and I ended up making a 3,000-foot descent to attempt to make the airport without turns.
During the descent, the windshield began to fog because it was cold soaked. It was not a little fog, but a lot of fog that completely blocked visibility out of the front and side. All the windows were fogged up in the super-moist tropical air of Colombia. As the descent progressed, I wondered if it was possible to land a King Air while wiping the window at the same time!
We wiped and wiped, turned on the windshield heat, and then my copilot had the brilliant idea to pull the Window Defog knob. Glorious, heated air began to blow on both the front and side windows, alleviating our problems. We put down our completely drenched napkins and were thankful that Beechcraft added this feature to the King Air.
Usually, we don’t see big problems with window fogging in the King Air, so we rarely use this switch. But when we get fogged windows, hopefully you’ll remember it is available. It’ll be the one that has dust on it from disuse.
There are many other dusty switches in a King Air, but this is a start. The next time you have a cross-country flight, I challenge you to pull out your pilot’s operating handbook and review each and every switch in your cockpit. It just might be a good reminder of things forgotten from your initial training. It might also help your brain and hand go to the right switch at the right time during that tough flight when the chips are down. Then, get out your tub of Clorox wipes and clean your airplane. I’m sure there’s dust on some of those switches!