曝光台 注意防骗
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that is not processed directly through the fovea will be
of less detail. An aircraft at a distance of 7 miles
which appears in sharp focus within the foveal center
of vision would have to be as close as 7/10 of a mile
in order to be recognized if it were outside of foveal
vision. Because the eyes can focus only on this
narrow viewing area, effective scanning is accomplished
with a series of short, regularly spaced eye
movements that bring successive areas of the sky into
the central visual field. Each movement should not
exceed 10 degrees, and each area should be observed
for at least one second to enable detection. Although
horizontal back−and−forth eye movements seem
preferred by most pilots, each pilot should develop a
scanning pattern that is most comfortable and then
adhere to it to assure optimum scanning.
6.3.3Studies show that the time a pilot spends on
visual tasks inside the cabin should represent no more
than 1/4 to 1/3 of the scan time outside, or no more than
4 to 5 seconds on the instrument panel for every
16seconds outside. Since the brain is already trained
to process sight information that is presented from
left to right, one may find it easier to start scanning
over the left shoulder and proceed across the
windshield to the right.
6.3.4Pilots should realize that their eyes may require
several seconds to refocus when switching views
between items in the cockpit and distant objects. The
eyes will also tire more quickly when forced to adjust
to distances immediately after close−up focus, as
required for scanning the instrument panel. Eye
fatigue can be reduced by looking from the
instrument panel to the left wing past the wing tip to
the center of the first scan quadrant when beginning
the exterior scan. After having scanned from left to
right, allow the eyes to return to the cabin along the
right wing from its tip inward. Once back inside, one
should automatically commence the panel scan.
6.3.5Effective scanning also helps avoid empty−
field myopia." This condition usually occurs when
flying above the clouds or in a haze layer that
provides nothing specific to focus on outside the
aircraft. This causes the eyes to relax and seek a
comfortable focal distance which may range from 10
to 30 feet. For the pilot, this means looking without
seeing, which is dangerous.
7. Judgment Aspects of Collision
Avoidance
7.1Introduction.The most important aspects of
vision and the techniques to scan for other aircraft are
described in paragraph 6 above. Pilots should also be
familiar with the following information to reduce the
possibility of mid−air collisions.
7.2Determining Relative Altitude.Use the horizon
as a reference point. If the other aircraft is above
the horizon, it is probably on a higher flight path. If
the aircraft appears to be below the horizon, it is
probably flying at a lower altitude.
ENR 1.15−8 AIP
15 MAR 07 United States of America
Nineteenth Edition Federal Aviation Administration
7.3Taking Appropriate Action.Pilots should be
familiar with right−of−way rules so immediate
evasive action can be taken if an aircraft is on an
obvious collision course. Preferably, such actions
will be in compliance with applicable Federal
Aviation Regulations.
7.4Consider Multiple Threats.The decision to
climb, descend, or turn is a matter of personal
judgment, but one should anticipate that the other
pilot may also be making a quick maneuver. Watch
the other aircraft during the maneuver and
immediately begin your scanning again since there
may be other aircraft in the area.
7.5Target Acquisition.Anticipate the target in the
location and ranges you are searching. Locate a
sizable, distant object (e.g., a cloud formation,
mountain peak, prominent landmark, building or
pier) that is within range of the anticipated target, and
focus your eyes on it as you begin each scan pattern.
7.6Collision Course Targets.Any aircraft that
appears to have no relative motion and stays in one
scan quadrant is likely to be on a collision course.
Also, if a target shows no lateral or vertical motion,
but increases in size,TAKE EVASIVE ACTION.
7.7Recognize High Hazard Areas
7.7.1Airways, and especially VORs, and Class B, C,
D, and E surface areas are places where aircraft tend
to cluster.
7.7.2Remember, most collisions occur during days
when the weather is good. Being in a radar
environment" still requires vigilance to avoid
collisions.
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AIP航行情报汇编3(9)
