User Guide

174
175
The airspeed will ultimately stabilize somewhere around
145-150 knots, depending on air temperature. That may not seem
all that fast for this airplane, but remember-that’s indicated air-
speed. At this altitude, true airspeed should be around 220 knots;
that’s better than 250 mph!
Note, however, that the fuel flow is still pretty high; if you
punch up the “hours remaining” display, you’ll notice that we
don’t have much time to enjoy our high speed. This is where lean-
ing the mixture helps a great deal. We’re probably starting out
with a fuel flow close to 30 gph. You can bring the mixture con-
trol back smoothly, but fairly quickly, until we get down to about
22 gph.
From here on, however, you’ll need to continue to lean
slowly and carefully, while watching TIT closely (make sure you
have it showing in the upper left digital display, if necessary by
pushing the button next to the TIT gauge). The system needs some
time to respond. As you continue to lean, the TIT will increase,
then start back down. This is the “peak,” and as it starts down
you’re on the lean side, which is not authorized for continuous
operation. Slowly re-enrich the mixture until it’s once again
reached its peak value-in fact, you may want to continue until it
just barely begins to decrease again, just to be sure you’re back on
the rich side.
Now look at the fuel flow. It should be down around 18 gph.
That’s a 40% reduction in fuel flow-or a 40% increase in range.
Looked at differently: the range figures in the pilot’s handbook are
based on proper leaning procedure. If you’ve planned and fueled
for a 1000-mile flight, and forget to lean, somewhere around 600
miles it’s going to get awfully quiet up there...
Before we head back down, let’s disengage the autopilot
and hand-fly for a moment. Compared to the 172, you may think
that the Mirage is sensitive in pitch: it’ll seem quite difficult to
hold altitude smoothly. Actually, it’s fairly heavy and stable in
pitch. What you’re seeing, instead, is the result of its significantly
higher cruising speed: it takes much less of a pitch change at these
speeds to cause a significant rate of climb or descent. The little dot
at the center of the artificial horizon is the same size as the hori-
zon line on the instrument. You may find that your corrections are
limited to half, or even one quarter, the diameter of that dot.
As you approach the course arrow this time, start reversing
the entire sequence. On your first left turn, retract one notch of flaps
and accelerate to 90 knots, without losing any altitude; on the sec-
ond turn, bring up the next notch and accelerate to 100 knots; on
the third, retract the gear; and, on the fourth, retract the final notch
of flaps and accelerate to cruise speed once again. Not easy, is it?
In one exercise, you’ve practiced just about all the basic airplane-
handling skills you’d need to fly an instrument approach.
UP, UP, AND AWAY
Before we do that, however, let’s make a brief excursion to
altitude to get a look at cruise power setting and mixture control.
Set cruise climb power of 35 in. Hg., 2500 RPM, and 32 gph fuel
flow, and trim the airplane for 125 knots. Note the rate of climb-
this thing is quite a performer. However, we’re going all the way
up to our maximum authorized altitude of 25,000 feet, so once
you’ve seen enough of how it handles in climb, go ahead and use
the simulator’s “slew” function to run up to 24,000 feet. Then
return to normal operation so we can make the last 1000 feet of
the climb, and the subsequent level-off, manually.
As we get to about 24,500 feet, bring the nose down just a
bit, so that we climb the last 500 feet at about 500 fpm on the VSI.
As we reach exactly 25,000 feet, ease the nose down until the
altimeter stops moving and the VSI zeros out. Stay ahead of the
trim as the airplane accelerates; it’ll keep on doing so for some
time. Finally, bring the throttle back to 32 in. Hg. and the prop
back to 2400 RPM. (If the engine can’t hold 32 in. Hg. at this
RPM, as might happen on a warm day, increase the RPM, using
the prop control, until it can.)
Let’s use the autopilot for a moment so we can concentrate
on leaning the mixture. Adjust the heading bug to line up right
under the lubber line at the top of the HSI, engage the autopilot,
and hit the HDG and ALT buttons so the airplane maintains its
current heading and altitude. Check the fuel gauges, too-this
might be the right time to switch tanks. If you haven’t changed the
rudder trim since leveling off, the ball is probably displaced a bit
to the left, so dial in just enough left rudder trim to recenter it.
Flight Instruction
Flight Instruction