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
visual after emerging from the
clouds during an approach. There
are various designs for various
purposes, shown in the AIP.
When approaching visually to a
runway, it's often useful to have an
aid to help get the glideslope right
(lateral guidance is provided by the
runway lights). Those described here
use different coloured light patterns
to show whether you are on a
glideslope, too high or too low. They
will be situated to the left of the
runway threshold and visible up to
about 5 nm by day and 20 nm or
more by night. Their sphere of
influence is ±10° of the extended
centreline, up to 4 nm.
VASIS
The Visual Approach Slope Indicator
System is a group of four lights (2-
bar), which may be turned off if the
weather is down to minimums so
they don't confuse you.
The light bars are called upwind and
downwind. There's a middle one for the
3-bar version - normal aircraft use
the middle and downwind ones, and
widebodies use the middle and
upwind bars to get a glideslope of 3°
(usually).
Normal means an eye-to-wheel height
of up to 25 feet (e.g. DC-8).
Widebodies have up to 45 feet.
When you are on the glideslope, you
should see red lights over white ones
("red on white, you're all right"). If
you are too low, you will see red
over red ("red on red, you're dead").
When the approach is correct, you
will be clear of obstructions within
6-9° either side of the centreline up
to 4 nm out, with a safe wheel
clearance over the threshold.
A Tri-Color VASI uses red, green
and amber to indicate too low, on
the glideslope and too high,
respectively.
Air Law 71
A Pulsating VASI (PVASI) uses a
single light source to project a twocolour
approach indication. When
very low or very high, the light
pulsates more in relation to your
distance away, otherwise it is steady
for on the glideslope (white) and just
below (red).
PAPI
The Precision Approach Path Indicator
does pretty much the same thing as
VASIS, but with 4 lights in a row:
When on the correct slope, the two
lights nearest the runway are red and
the two furthest ones show white.
Three whites and a red mean slightly
high, and three reds and a white
means slightly low. Four of each is
way too much.
T-VASIS
This uses 10 lights, with 4 horizontal
ones in the middle and the other 6 as
3 vertical groups above and below,
which only appear when you are low
or high. If you do things properly,
you will arrive at the threshold at 45
feet. All lights are white, except
where a gross undershoot is involved,
when they turn red.
Lights above the horizontal 4 are the
fly down lights, whereas those
appearing below are the fly up ones.
Cruising Altitudes
Here, you have to take into account
obstacles, aircraft performance and
weather. What height you fly at is
determined by the direction in which
you are going, for which, unless told
otherwise, you use magnetic track in
the SDA and true track in the NDA.
VFR Below 18,000 feet
2,000 feet separation, as follows (but
not below 3,000 feet):
000-179° 180-369°
Odd levels, plus 500 feet
(3,500, 5,500 etc)
Even levels, plus
500 feet (4,500,
6,500, etc)
IFR/CVFR below 18,000 feet
2,000 feet separation, as follows (but
not below 3,000 feet):
000-179° 180-369°
Odd levels (3,000,
5,000 etc)
Even levels (4,000,
6,000, etc)
Exceptions in CFS do not apply to
VFR flights. High level airspace may
be structured for one-way traffic at
times, and non-appropriate levels
will be used.
Minimum Altitudes
VFR
Unless taking off, approaching or
landing as described in 602.12, or as
permitted under 602.15, you may not
overfly a built-up area or open-air
assembly of people, unless you are
high enough to land without creating
a hazard to people or property on
the surface and, in any case, at least
1,000 feet above the highest obstacle
within 2,000 feet from an aeroplane,
500 feet above the highest obstacle
within 500 feet from a balloon, or
72 Canadian Professional Pilot Studies
1,000 feet above the highest obstacle
within 500 feet of anything else.
Otherwise, you may not fly closer
than 500 feet to any person, vessel,
vehicle or structure.
For sections 602.13, 14 and 15, you
are "overhead" within 500 feet
horizontally from a helicopter or
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：
Canadian Professional Pilot Studies1(51)
