Excellent! Thanks. So let me see if I have this right; After engine start
the condition levers would be in ground (low) idle through taxi and takeoff
and I would move them to flight (high) idle at cruise. They would stay at
flight idle through descent, approach, and landing and then moved to ground
idle during thrust reversal in preparation for taxi again. Sound ok?

"CFII_ASC" wrote in message
ps.com...
Hi,

The condition levers are the analog of the mixture controls. They are
coded the same color (red), and in the same position on the quadrant
(far right) as mixtures, but they actually do not do the same thing as
mixture controls.

A mixture control changes the air-fuel ratio (piston engine). In the
turbine, the condition lever is used to control whether fuel is going
to the engine or not (bottom stop is CUT-OFF). The other two positions
set the idle speed of the engine, i.e. what turbine (N1) speed the
engine will run at when the 'power levers' (those black things that we
call throttles) are pulled back to the idle position. The mixture is
actually controlled automatically by the fuel controller.

So, for example, in a King Air, you have Power Levers, Prop Levers, and
Condition Levers; they look much the same and are in the same positions
as the throttles, prop and mixture controls in a piston twin.

The effect of the condition levers is to either 1) shut off fuel to the
engine (cut-off), or to set the idle governed speed for ground
operations (typically 25% N1), or to set the idle speed for flight
operatons (typically 50% N1). They have these two settings because the
turbines have so much power at flight idle that on the ground you
wouldbe constantly riding the brakes to maintain a safe taxi speed, and
scattering miscellaneous small aircraft in your prop blast as you
maneuvered on the airport. The machine is much easier to manage on the
ground with and idle of 25% N1. However, if we used ground idle in
flight, at idle power the drag on those two huge props would be
excessive, and the airplane would develop a dangerously high sink rate
if the pilot ever pulled back to idle, say on a slightly high approach
on final. Compounding this problem is the long spool-up time the
engine would require if the pilot suddenly decided he wanted power
again after letting the engine spin down to 25% N1 (Remember the Paris
Airshow crash of the Airbus?) So, in flight we keep the condition
levers in the Flight Idle stop, so that if we ever pull the power
levers back to idle on final we won't make one of those big, smoking
holes in the ground just short of the runway.

Right after touchdown it gets a little busy as you come in with the
brakes, pull the power levers up and over their lockouts and back into
the thrust reverse positions; then move back over to the condition
levers and pull them back into ground idle so that once we come out of
reverse we will not have the flight idle thrust fighting the brakes;
but then we have to bring the right hand back over to the power levers
and bring them forward, out of reverse before we get below about 40
KIAS, because at those speeds in reverse the props tend to suck things
up off the runway and get damaged (really expensive) so we put them
forward as we hit 40. While you are doing all of this with your right
hand, your left hand has to be holding the elevator back (ugh) by
itself, your feet have to keep us on the centerline and your toes have
to apply just enough equal braking pressure so that we stop in time,
but not so much that we trigger the anti-lock system and scare all the
passengers.

that's a normal landing... add a slick runway and a stiff crosswind and
you will be just a little more busy...

Regards,

Gene
CFII, MEI, ASC