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Emergency or abnormal situations can occur during
a takeoff that will require you to reject the takeoff
while still on the runway. Circumstances such as a
malfunctioning powerplant, inadequate acceleration,
inadequate wing kiting, runway incursion, or air traffic
conflict may be reasons for a rejected takeoff.
Prior to takeoff, you should have in mind a point along
the runway at which the powered parachute should
be airborne. If that point is reached and the powered
parachute is not airborne, take immediate action to
discontinue the takeoff. Properly planned and executed,
chances are excellent the powered parachute can
be stopped on the remaining runway without using
extraordinary measures, such as excessive braking or
trying to stop by using your feet as brakes. Neither
of these measures should be used and may result in
powered parachute damage and/or personal injury. In
the event a takeoff is rejected, reduce the power to idle
and shut down the engine. Immediately, pull down the
trailing edge to collapse the wing so it can be used as
a drogue chute, semi-inflated behind you.
Urgency characterizes all power loss or engine failure
occurring after lift-off. In most instances, the pilot has
only a few seconds after an engine failure to decide
and execute the proper course of action. In the event
of an engine failure on initial climb-out, the powered
parachute will be at a high pitch angle, with the cart
well in front of the wing. When the engine fails, the
cart will rock back under the parachute, possibly causing
a temporary but potentially dangerous dive. The
level of danger in the dive is dependent on how high
the PPC is above the ground when the engine fails.
The best situation is if the pilot can establish a normal
7-8
glide and execute a normal engine-out landing (see
Chapter 12). However, if the engine-out occurs close
to the ground, it may be necessary to immediately
flare the parachute so the parachute does not rotate
over the cart and into a dive which will increase the
descent rate.
Runway Surface and Gradient
Runway conditions affect takeoff performance. Typically,
powered parachutes take off from level grassy
surfaces. However, runway surfaces vary widely from
one airport to another. The runway surface for a specific
airport is noted in the Airport/Facility Directory
(A/FD). Any surface that is not hard and smooth will
increase the ground roll during takeoff. This is due
to the inability of the tires to smoothly roll along the
surface. Tires can sink into soft, grassy, or muddy
runways. Holes or other ruts in the surface can be
the cause of poor tire movement along the surface.
Obstructions such as mud, snow, or standing water
reduce the powered parachute’s acceleration down
the runway. Many of these same hindrances are multiplied
in effect by the use of soft or wide tires that
increase resistance themselves.
The gradient or slope of the runway is the amount of
change in runway height over the length of the runway.
The gradient is expressed as a percentage such
as a 3 percent gradient. This means that for every 100
feet of runway length, the runway height changes by
3 feet. A positive gradient indicates that the runway
height increases, and a negative gradient indicates that
the runway decreases in height. An upsloping runway
impedes acceleration and results in a longer ground
run during takeoff. A downsloping runway aids in acceleration
on takeoff resulting in shorter takeoff distances.
Runway slope information is contained in the
Airport/Facility Directory.
Takeoff Performance
Takeoff performance is partly a condition of accelerated
motion. For instance, during takeoff, the powered
parachute starts at zero speed and accelerates to
inflate the wing, then to takeoff speed and becomes
airborne. The important factors of takeoff performance
are as follows:
• The takeoff speed.
• The rate of acceleration during the takeoff roll.
• The takeoff roll distance is a function of both
acceleration and speed.
The minimum takeoff distance is of primary interest
in the operation of any powered parachute because
it defines the runway requirements. The minimum
takeoff distance is obtained by taking off on a length
of runway that allows sufficient margin to inflate the
wing, perform the LOC procedure, and then satisfactory
room to initiate a lift-off and climb.
The powerplant thrust is the principal force providing
the acceleration and — for minimum takeoff distance
— the output thrust should be at the maximum after
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Powered Parachute Flying Handbook动力伞飞行手册(63)
