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What are condition levers for?

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newmei

Well-known member
Joined
Nov 26, 2001
Posts
181
This one always bugs me........
I know some condition levers raise and lower the idle speed but what is the purpose???????? To control taxi speed?

Also is it true that some King Airs have only two propeller settings, climb and cruise?

I can't find this anywhere.
Thanks
 
Condition levers are first cousins to mixture levers on a piston aircraft, but they are used to set fuel flow for starting and taxi, and are advanced before takeoff.

They don't control mixture, though. That is done by the FCU, or fuel control unit.
 
but they are used to set fuel flow for starting and taxi, and are advanced before takeoff.

They don't have to be advanced before takeoff......low idle is just fine.....there are 2 settings that you can use ...low and high idle.
The difference between the two is just the idle speed of the N1 turbine. The reason why you would want to change the idle speed of the engine is mainly to handle increased electrical loads, especially with one engine inop.
 
Maybe it's just airplane type specific, but I was told by a guy who has flown turboprops for over 16 years to "never" take off without advancing the condition levers.

Perhaps this has to do with the type of FCU being used. The guy flew Garrett engines. Does that make sense?
 
Maybe it's just airplane type specific, but I was told by a guy who has flown turboprops for over 16 years to "never" take off without advancing the condition levers.


Could be.....i never flew a garret engine so I don't know what the procedures are for them
 
Ok so your sitting on the ramp with the engine sucking banging and blowing......

You are at low idle power levers at idle does the aircraft creep forward?


High idle power levers at idle does the aircraft creep forward?

Still confused
thanks
 
I think it definitely varies by aircraft. In the Saab, you can select Ground of flight idle, but you do it with the POWER levers. The Condition levers had a detent for Fuel Off (full aft), another detent for Start (slightly forward, but still in what we call the "feather" range.) Then you lift them over a gate to the "min/max" range where they become just like prop levers in a piston.
 
I don't recall that the idle speed made a whole lot of difference in the plane I flew. I'm not a turboprop expert, but it seemed to be anxious to get going, even with the power levers back against the gate. Lifting the locks and going back into beta a little helped keep me off the brakes. Some friends fly the King Air 200, and I noticed the same thing when I flew with them. My instructor said to avoid pulling back into beta while on the taxi, but he wasn't really clear why, perhaps the issue was cooling properly prior to shutdown.

Man, those garrets are LOUD. Glad we had the ANR headsets.
 
Nice FlyinBrian...............You got most of it, but remember Bottom Governing. Props are maintained at 1040RPM (or 1200PRPM in reverse) and the Power Levers control blade angle on the ground. Bottom Governing is disabled with the Power Levers above the 64 degree switch which then the Condition Levers Control PRPM. Essintially on the ground Power Levers control Blade Angle and Condition Levers control Fuel. In flight Power Levers control Fuel and Condition Levers control Blade Angle.

My take on Condition Levers are that they are airplane specific. Usually used for Prop Control and Fuel control. (but not exclusively.)
 
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Garrett engines must be in high idle. Imagine a helicopter at idle trying to fly, same idea.

PT6's, like most King Airs, use idle speeds for electrical loads, air conditioning, engine cooling, taxi speed, lower landing speed vs. quicker into reverse. Assuming that none of that mattered, you can have them in any position for takeoff on a PT6 because as soon as you advance the power levers, the engine leaves idle anyhow.
 

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