曝光台 注意防骗
网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
of attack (stall) where the relative lift decreases and
drag increases.
A spin is caused when the airplane’s wing exceeds its
critical angle of attack (stall) with a sideslip or yaw
acting on the airplane at, or beyond, the actual stall.
During this uncoordinated maneuver, a pilot may not
be aware that a critical angle of attack has been
exceeded until the airplane yaws out of control toward
the lowering wing. If stall recovery is not initiated
immediately, the airplane may enter a spin.
If this stall occurs while the airplane is in a slipping or
skidding turn, this can result in a spin entry and
rotation in the direction that the rudder is being
applied, regardless of which wingtip is raised.
Many airplanes have to be forced to spin and require
considerable judgment and technique to get the spin
started. These same airplanes that have to be forced to
spin, may be accidentally put into a spin by
mishandling the controls in turns, stalls, and flight at
minimum controllable airspeeds. This fact is additional
evidence of the necessity for the practice of stalls until
the ability to recognize and recover from them
is developed.
Often a wing will drop at the beginning of a stall.
When this happens, the nose will attempt to move
(yaw) in the direction of the low wing. This is where
use of the rudder is important during a stall. The
correct amount of opposite rudder must be applied to
keep the nose from yawing toward the low wing. By
maintaining directional control and not allowing the
nose to yaw toward the low wing, before stall recovery
is initiated, a spin will be averted. If the nose is allowed
to yaw during the stall, the airplane will begin to slip in
the direction of the lowered wing, and will enter a spin.
An airplane must be stalled in order to enter a spin;
therefore, continued practice in stalls will help the pilot
develop a more instinctive and prompt reaction in
recognizing an approaching spin. It is essential to learn
to apply immediate corrective action any time it is
apparent that the airplane is nearing spin conditions. If
it is impossible to avoid a spin, the pilot should
immediately execute spin recovery procedures.
SPIN PROCEDURES
The flight instructor should demonstrate spins in those
airplanes that are approved for spins. Special spin
procedures or techniques required for a particular
airplane are not presented here. Before beginning any
spin operations, the following items should be
reviewed.
• The airplane’s AFM/POH limitations section,
placards, or type certification data, to determine if
the airplane is approved for spins.
• Weight and balance limitations.
• Recommended entry and recovery procedures.
• The requirements for parachutes. It would be
appropriate to review a current Title 14 of the
Code of Federal Regulations (14 CFR) part 91 for
the latest parachute requirements.
A thorough airplane preflight should be accomplished
with special emphasis on excess or loose items that
may affect the weight, center of gravity, and controllability
of the airplane. Slack or loose control cables
(particularly rudder and elevator) could prevent full
anti-spin control deflections and delay or preclude
recovery in some airplanes.
Prior to beginning spin training, the flight area, above
and below the airplane, must be clear of other air
traffic. This may be accomplished while slowing the
airplane for the spin entry. All spin training should be
initiated at an altitude high enough for a completed
recovery at or above 1,500 feet AGL.
It may be appropriate to introduce spin training by first
practicing both power-on and power-off stalls, in a
clean configuration. This practice would be used to
familiarize the student with the airplane’s specific stall
and recovery characteristics. Care should be taken with
the handling of the power (throttle) in entries and
during spins. Carburetor heat should be applied
according to the manufacturer’s recommendations.
There are four phases of a spin: entry, incipient,
developed, and recovery. [Figure 4-10 on next page]
ENTRY PHASE
The entry phase is where the pilot provides the
necessary elements for the spin, either accidentally or
intentionally. The entry procedure for demonstrating a
spin is similar to a power-off stall. During the entry,
the power should be reduced slowly to idle, while
simultaneously raising the nose to a pitch attitude that
will ensure a stall. As the airplane approaches a stall,
smoothly apply full rudder in the direction of the
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：
AIRPLANE FLYING HANDBOOK 飞机飞行手册上(49)
