What are condition levers for?

[newmei]

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]

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]

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]

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]

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]

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]

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]

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]

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.)

 

[flint4xx]

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]

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]

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]

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

 

[Cornelius]

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]

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.

 

[sabreliner]

Cornelius;

Good timing, ehh?!?!

Pure luck. Any questions?

 

[Spiraldive]

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

"Air brakes"

 

[Cornelius]

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]

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]

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

 

[Jetjr]

Here's a "quick and to the point" answer.

On the Beech 1900 D (PT6) low idle is 68% N1 and High idle is 72% N1. The higher idle will get you faster taxi speeds but the you end up riding the brakes, but the more useful applications are to 1) because the engine is running at a higher rpm, there is less load-stress-heat on the generator when trying to start the second engine, 2) there is better airflow through the engine therefore lower temps inside the engine, 3) the higher rpm helps the Vapor Cycle Machine aka R12 Air Conditioner work better...(Ground ops), 4) the engine responds (spools up) MUCH more quickly from 72%...so you should ALWAYS have your condition lever set to high idle in flight so that you have much better throttle response while maneuvering.

OK....do I win a prize?

 

[F4U]

No doubt about it. Condition Levers and what they actually do are specific to each aircraft.

In the Cessna Conquest the Condition Levers select fuel on or fuel off to the engines, they have no other function as far as the pilot is concerned.

In the Dash on the other hand the Condition Levers do alot of different things.

Provide Fuel On and Fuel Off for engine starting.
Feathers and Unfeathers the Prop.
Used to Set Propeller RPM in the Forward Thrust Range (past the prop min gate)

Changing the Condition Lever Angle between the MIN and MAX postions selects any desired propeller speed between 900 and 1200 rpm. 900 rpms are normally selected for Cruise and 1200 rpms for takeoff, Single Engine Operations, After touchdown to provide for better braking in the discing and reverse regions, and to assist the props in getting rid of sufficient buildups of ice. 1050 rpms is normally used for enroute climb and landings.

 

[Simon Says]

F4U,

Do you fly for Horizon? I ask because of the 900PRPM cruise thing. I thought only Horizon pulls them back that much, or if that is normal with the Dash.

 

[NEDude]

More on aircraft specific condition lever stuff. In the PC-12 you do advance to high idle prior to takeoff. The PC-12 has a virtually identical engine to the Beech-1900D (PT6A-67), but as has been said, in the Beech you do not need the condition levers to be in high idle for flight.

 

[sabreliner]

F4U,

Do you fly for Horizon? I ask because of the 900PRPM cruise thing. I thought only Horizon pulls them back that much, or if that is normal with the Dash.

I don't know if he flies for Horizon or not...

but 900 RPM is the normal cruise setting, at least on the -100, 200 and 300. We would climb usually at 1050, then cruise at 900, though you could also climb at 900 if you really wanted it quiet. The roughly 12ft diameter props on the -100 didn't really need to turn much faster than that.

I flew them at ALG, and PDT also did it the same.

 

[xjcaptain]

Mesaba used the same procedure when we had our dash8-100's. Takeoff was 1200RPM then 900 was used for climb and cruise. About the only time we used 1050 in the climb was in icing conditions. Now we have the Saab's and we only wish we still had the dash-8's!

 

[surplus1]

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

Cornelius,

When you get to GS learn everything you can about the propellers on this aircraft. Remember their limitations and don't exceed them. Don't let anyone make you believe that any of them can be ignored.

This particular aircraft has a history of very serious problems related to its propeller. Learn about them.

I am not trying to scare you, but the propeller problems have been very serious. Reportedly, the biggest one has been "fixed" and I don't know of any recent incidents. Just the same, this propeller on this airframe has killed more than once, so pay attention.

Also, pay close attention to operation in icing conditions. There has been more than one upset due to ice accretion.

Yes, I've flown it and have a lot of time in the aircraft. Despite the problems, it is a fun airplane to fly and I enjoyed it a lot. It's the equivalent of a modern DC-3. Carries the same # of people, twice as high and twice as fast. My second most favorite turboprop and a great little airplane.

PS. If you get about 5 kias slower than the max flap speeds BEFORE you extend the flaps, most of your flap problems will vanish.

You'll have fun when you learn you can pass the "Swedish Helicopter" with one feathered.

 

[Cornelius]

Thanks, I am going to research some of the EMB-120 history next week. I know of the ASA EMB120 prop breakup that was pretty serious. I don't know of any icing accidents it has had. I'll check it out though.

 

[MartinFierro]

I have heard through the grapevine that fairly recently an ASA Brakillya lost control of a prop, it went to 160%. Luckily it was already over the runway and no one was hurt. Cause is still undetermined. This is well after the problem which caused the other ASA Brasilia to go down several years ago was addressed. As for icing, last year or year before I believe a Comair E120 iced up in Florida, lost a lot of altitude and had structural damage. Then if memory serves me, there was another Comair E120 that crashed up north somewhere (possibly CVG?) due to ice.

 

[F4U]

I fly Dash's for CCAir.

How much longer I will be flying Dash's there remains to be seen.

A letter is out indicating we are shutting down on July 1, 2002.