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wider area of scan while circling.
Once a landmark is located on the sectional and on the
ground, confirm the location by finding a few other
nearby landmarks. For instance, if that is a town below,
then the highway should curve like the one shown on
the chart. Does it? If lost and near a suitable landing
area, make certain not to leave the area until certain of
your location. Airport runways sometimes provide
valuable clues. The airport name is often painted right
on the runway. Failing that, the runway orientation
itself may indicate the airport.
If all efforts fail, attempt a radio call to other soaring
pilots in the area. A description of what is below and
nearby may bring help from a fellow pilot more familiar
with the area.
CROSS–COUNTRY USING A
SELF-LAUNCHING GLIDER
A self-launch glider can give the pilot much more
freedom in exchange for a more complex and expensive
aircraft. First, a self-launch glider allows the pilot
to fly from airports without a towplane or towpilot.
Second, the engine can be used to avoid off-field landings
and extend the flight. In theory, when low in a
self-launcher, simply start the engine and climb to
the next source of lift. This second advantage has
pitfalls and dangers of its own and has lead to many
accidents due to engine failure and/or improper
starting procedures. Engines on self-launch gliders
are generally not quite as reliable as those on airplanes
and are susceptible to special problems. For
instance, in the western United States, summer thermals
often extend to altitudes where the air is cold.
The self-launch engine can become cold soaked,
after several hours of flight and may take more time
to start or may fail to start altogether.
Over reliance on the engine may result in a false
sense of security. This can lead pilots to glide over
unlandable terrain, something they might not normally
do. If the engine then fails just when needed
most, the pilot has no safe place to land. Some accidents
have occurred when the engine starting system
was actually fully functional, but in the rush to start
the engine to avoid landing, the pilot did not perform
a critical task, such as switching the ignition on.
Other accidents have occurred when the engine did
not start right away, and while trying to solve the
starting problem, the pilot flew too far from a suitable
landing area. For self-launch gliders with an
engine that stows in the fuselage behind the cockpit,
the added drag of an extended engine can reduce the
glide ratio by 50 to 75 percent![Figure 11-15]
The critical decision height to commit to an engine
start on a self-launch glider is typically higher than the
minimum to commit to landing of a non-powered
glider. This is due to a combination of time needed to
actually start the engine and extra drag during the
starting process. It may take anywhere from 200 feet
to 500 feet of altitude to extend and start the engine.
Whereas a pure glider may commit to landing at 1,000
11-15
feet AGL, the self-launch pilot will likely opt for 1,500
feet AGL, depending on the glider and landing options
should the engine fail. In this sense, the self-launch
glider becomes more restrictive.
Cross-country flight can also be done under power with
a self-launching glider, or a combination of powered
and soaring flight. For some self-launch gliders, the
most efficient distance per gallon of fuel is achieved by
a maximum climb under power followed by a poweroff
glide. Check the GFM/POH for recommendations.
Another type of glider features a sustainer engine.
These engines are not powerful enough to self-launch
but are able to keep the glider airborne if lift fails. The
sustainer engine is typically less complex to operate
than their self-launch counterparts, and can eliminate
the need for a time-consuming retrieve. Pilots flying
with a sustainer are susceptible to the same pitfalls as
their self-launch counterparts.
HIGH–PERFORMANCE GLIDER
OPERATIONS AND CONSIDERATIONS
Extended cross-country flights have been made in relatively
low-performance gliders. However, on any given
soaring day, a glider with a 40-to-1 glide ratio will be
able to fly farther and faster than one with 20-to-1,
assuming the pilots in each have similar skill levels.
Often a glider pilot looks for more performance in a
glider to achieve longer and faster cross-country flights.
High-performance gliders are usually more complex
and somewhat more difficult to fly, but they vary considerably.
Current Standard Class gliders (15-meter
　
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本文鏈接地址：Glider Flying Handbook(158)