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avoid leeward turbulence and keep the helicopter
within reach of a forced landing area as long as
possible.
On landing, take advantage of the long axis of the area
when wind conditions permit. Touchdown should be
made in the forward portion of the area. Always perform
a stability check, prior to reducing r.p.m., to
ensure the landing gear is on firm terrain that can safely
support the weight of the helicopter.
TAKEOFF
Apinnacle takeoff is an airspeed over altitude maneuver
made from the ground or from a hover. Since
pinnacles and ridgelines are generally higher than the
immediate surrounding terrain, gaining airspeed on the
takeoff is more important than gaining altitude. The
higher the airspeed, the more rapid the departure from
slopes of the pinnacle. In addition to covering unfavorable
terrain rapidly, a higher airspeed affords a more
favorable glide angle and thus contributes to the
chances of reaching a safe area in the event of a forced
landing. If a suitable forced landing area is not available,
a higher airspeed also permits a more effective
flare prior to making an autorotative landing.
On takeoff, as the helicopter moves out of ground
effect, maintain altitude and accelerate to normal climb
airspeed. When normal climb speed is attained, establish
a normal climb attitude. Never dive the helicopter
down the slope after clearing the pinnacle.
COMMON ERRORS
1. Failure to perform, or improper performance of, a
high or low reconnaissance.
2. Flying the approach angle at too steep or too shallow
an approach for the existing conditions.
3. Failure to maintain proper r.p.m.
4. Failure to consider emergency landing areas.
5. Failure to consider how wind and turbulence
could affect the approach and takeoff.
Figure 10-9. When flying an approach to a pinnacle or ridgeline,
avoid the areas where downdrafts are present, especially
when excess power is limited. If you encounter
downdrafts, it may become necessary to make an immediate
turn away from the pinnacle to avoid being forced into the
rising terrain.
Airspeed over Altitude—This means that in this maneuver, obstacles
are not a factor, and it is more important to gain airspeed than altitude.
10-10
11-1
Today helicopters are quite reliable. However
emergencies do occur, whether a result of mechanical
failure or pilot error. By having a thorough knowledge
of the helicopter and its systems, you will be able to
more readily handle the situation. In addition, by
knowing the conditions that can lead to an
emergency, many potential accidents can be avoided.
AUTOROTATION
In a helicopter, an autorotation is a descending maneuver
where the engine is disengaged from the main rotor
system and the rotor blades are driven solely by the
upward flow of air through the rotor. In other words, the
engine is no longer supplying power to the main rotor.
The most common reason for an autorotation is an
engine failure, but autorotations can also be performed
in the event of a complete tail rotor failure, since there
is virtually no torque produced in an autorotation. If
altitude permits, they can also be used to recover from
settling with power. If the engine fails, the freewheeling
unit automatically disengages the engine from the
main rotor allowing the main rotor to rotate freely.
Essentially, the freewheeling unit disengages anytime
the engine r.p.m. is less than the rotor r.p.m.
At the instant of engine failure, the main rotor blades
are producing lift and thrust from their angle of attack
and velocity. By immediately lowering collective pitch,
which must be done in case of an engine failure, lift and
drag are reduced, and the helicopter begins an immediate
descent, thus producing an upward flow of air
through the rotor system. This upward flow of air
through the rotor provides sufficient thrust to maintain
rotor r.p.m. throughout the descent. Since the tail rotor
is driven by the main rotor transmission during autorotation,
heading control is maintained as in normal flight.
Several factors affect the rate of descent in autorotation;
density altitude, gross weight, rotor r.p.m., and
airspeed. Your primary control of the rate of descent is
airspeed. Higher or lower airspeeds are obtained with
the cyclic pitch control just as in normal flight.
In theory, you have a choice in the angle of descent
varying from a vertical descent to maximum range,
which is the minimum angle of descent. Rate of descent
is high at zero airspeed and decreases to a minimum at
approximately 50 to 60 knots, depending upon the particular
　
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