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and considerations to keep in mind are:
• Maintain positive control of the airplane and
establish the best glide configuration and airspeed.
Turn the airplane towards an airport or away from
congested areas.
• Check to determine the cause of the engine
malfunction, such as the position of fuel selectors,
magneto switch, or primer. If possible, the
cause of the malfunction should be corrected
immediately and the engine restarted.
• Announce the emergency situation to Air Traffic
Control (ATC) or UNICOM. If already in radio
contact with a facility, do not change frequencies,
unless instructed to change.
• If the condition of the nearby terrain is known,
turn towards an unlighted portion of the area.
Plan an emergency approach to an unlighted
portion.
• Consider an emergency landing area close to
public access if possible. This may facilitate
rescue or help, if needed.
• Maintain orientation with the wind to avoid a
downwind landing.
• Complete the before landing checklist, and
check the landing lights for operation at altitude
and turn ON in sufficient time to illuminate the
terrain or obstacles along the flightpath. The
landing should be completed in the normal landing
attitude at the slowest possible airspeed. If
the landing lights are unusable and outside visual
references are not available, the airplane should
be held in level-landing attitude until the ground
is contacted.
• After landing, turn off all switches and evacuate
the airplane as quickly as possible.
Ch 10.qxd 7/13/04 11:10 AM Page 10-8
11-1
HIGH PERFORMANCE AND COMPLEX
AIRPLANES
Transition to a complex airplane, or a high performance
airplane, can be demanding for most pilots without previous
experience. Increased performance and increased
complexity both require additional planning, judgment,
and piloting skills. Transition to these types of
airplanes, therefore, should be accomplished in a
systematic manner through a structured course of
training administered by a qualified flight instructor.
A complex airplane is defined as an airplane equipped
with a retractable landing gear, wing flaps, and a
controllable-pitch propeller. For a seaplane to be
considered complex, it is required to have wing flaps and
a controllable-pitch propeller. A high performance
airplane is defined as an airplane with an engine of more
than 200 horsepower.
WING FLAPS
Airplanes can be designed to fly fast or slow. High
speed requires thin, moderately cambered airfoils with
a small wing area, whereas the high lift needed for low
speeds is obtained with thicker highly cambered
airfoils with a larger wing area. [Figure 11-1] Many
attempts have been made to compromise this
conflicting requirement of high cruise and slow
landing speeds.
Since an airfoil cannot have two different cambers at
the same time, one of two things must be done. Either
the airfoil can be a compromise, or a cruise airfoil can
be combined with a device for increasing the camber of
the airfoil for low-speed flight. One method for varying
an airfoil’s camber is the addition of trailing edge flaps.
Engineers call these devices a high-lift system.
FUNCTION OF FLAPS
Flaps work primarily by changing the camber of the
airfoil since deflection adds aft camber. Flap deflection
does not increase the critical (stall) angle of attack, and
in some cases flap deflection actually decreases the
critical angle of attack.
Deflection of trailing edge control surfaces, such as the
aileron, alters both lift and drag. With aileron
deflection, there is asymmetrical lift (rolling moment)
and drag (adverse yaw). Wing flaps differ in that
deflection acts symmetrically on the airplane. There is
no roll or yaw effect, and pitch changes depend on the
airplane design.
Straight
Elliptical
Tapered
Sweptback
Delta
Figure 11-1. Airfoil types.
Ch 11.qxd 5/7/04 8:50 AM Page 11-1
11-2
Pitch behavior depends on flap type, wing position,
and horizontal tail location. The increased camber
from flap deflection produces lift primarily on the rear
portion of the wing. This produces a nosedown
pitching moment; however, the change in tail load
from the downwash deflected by the flaps over the
horizontal tail has a significant influence on the
pitching moment. Consequently, pitch behavior
depends on the design features of the particular airplane.
Flap deflection of up to 15° primarily produces lift
with minimal drag. The tendency to balloon up with
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AIRPLANE FLYING HANDBOOK 飞机飞行手册下(9)
