What are condition levers for?

newmei

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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
 

Timebuilder

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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.
 

Jack Hass

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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.
 

Timebuilder

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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?
 

Jack Hass

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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
 

newmei

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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
 

FlyinBrian

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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.
 

Timebuilder

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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.
 

Simon Says

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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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flint4xx

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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.
 

rightrudder

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Condition levers have different functions in different aircraft. In some (the Dash 8 and DO328, for example) they introduce fuel and cut it off as well as set propeller rpm.

For a good explanation of turbine systems, check out "The Turbine Pilots Flight Manual" by Greg Brown and Mark Holt.

RR
 

MartinFierro

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I agree I think it depends on the aircraft. I think King Airs and maybe the 1900 have three sets of levers? Maybe not. At any rate, the Saab and others have just 2: power and condition. In the slaab the condition levers don't really change the engine speed (Ng) except for when you unfeather the props. The rest is done with the power levers. With the power levers in the ground idle range and the prop unfeathered, the power levers control the blade angle, which helps controls your thrust for taxi.
 

chperplt

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In the 1900, we have three sets.. Power, Prop, and Condition. Condition levers are in low or high and control idle N1 speed.
 

Cornelius

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Can someone explain what the EMB-120 power quadrant is like. There are only two levers and I'm a little confused as to the operation of the levers.
 

sabreliner

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The function of the condition levers is different on every installation. On the E-120, the position of the levers serves many purposes. They feather the prop, and set the governors to control prop speed in flight. They also actuate the fuel shutoffs.

With the EEC, or Electronic Engine Control,functioning they also serve to govern engine speeds to certain minimum values on the ground. With the condition lever in feather, the engine Nh is governed to a min of 62%. Between Min RPM and Max RPM, the Nh is governed to a min of 50%. At max RPM, the Nh is governed to a min of 65%.

There are several reasons you would want these various values. On the ground, 50% Nh generally provides pleanty of thrust to manuver the airplane in beta range on the power levers. (Beta range being the area below flight idle and above reverse where the power levers directly control prop blade angle.) This lower engine speed allows us to better control the taxi speed without having to use the brakes. Also, on the Brasilia, RPM above 60% on the ground is to be avoided due to some sort of odd prop stress. Wouldn't want to have a prop blade come off at an inopportune moment, nowwould we.

With the condition levers at Max (as they would be for takeoff and landing) you get not only higher prop RPM, but an engine that is already spooled for takeoff, max reverse, or a possible go around, increasing you performance. Having the engine spooled up decreases the engine response time to power lever increases, giving you more instantaneous response.

Like I said earlier, this is one installation, on one airplane. It is bound to be different on many other A/C.
 

Spiraldive

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Hmm. I've found that the phonetic pronounciation of "condition lever" is the most useful description.

"Air brakes" :D :D :D
 

Cornelius

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Thanks Sabreliner, I may be assigned the EMB-120 tomorrow, which I just found out today, so I'm doing just a bit of research. The Brasilia sounds like it is going to be a little more demanding than the mighty 1900D. Great explanation.

C-ya
 

T-handle

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good answer for saab condition levers

Simon Says,

Good simple explanation.

It's too bad that our Mesaba APDs won't take that as an answer on a type rating oral!
 

Simon Says

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LOL.........I just got back from my PC, that is how I am so hip on this stuff.
 
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