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Classification and characteristics of airports. |
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a) Airports Classification
The classification of the
airports is based
on the characteristics
of the "critical
aircraft". The critical
aircraft is
the airplane with the highest
requirements
that can use the airport.
In accordance with
its own characteristics
to each airport is
assigned a code number
and a code letter.
The code number refers
to the airplane reference
field lenght; in the reference
field lenght
the stop way and the clear
way are included
aswell. The code letter
refers to the critical
airplane's wing span and
the distance that
it's between the external
extremities of
the wheels of its main
landing gear. An aerodrome's
reference code may be 1A,
2B, 3C, 4D, 4E,
4F.
b) Airport's Characteristics
An airport consists of
a movement area and
a manoeuvring area. The
movement area consists
of parking spaces (gates,
ramps) and manoeuvring
area; the manoeuvring area
consists of taxi
ways and runways. Regarding
the runway is
worth to mention that its
longitudinal slope
must not be above 1% for
runways code number
3 and 4, and not above
2% for a runway that
is code number 1 or 2,
while the transversal
slope must not be above
1.5% for a runway
that is code letter C,
D, E, F and not above
2% for runways code letter
A or B. Moreover,
regarding runways, is worth
to say that there
are instrument runways
and non instrument
runways; the instrument
runways are divided
in precision runways and
non precision runways;
moreover, depending on
the ILS system (Instrument
Landing System) available,
a precision runway
can be of one of the following
categories:
1, 2, 3A, 3B, 3C.
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Runways and stop ways are positioned within
so called runway strips, which have the purpose
to reduce the damage to the aircraft in case
this one would run out of the runway. The
stop way is a bidimensional area of the same
width of the runway, placed at both extremities
of the runway in order to make available
a longer distance for stopping to aircraft
which fail to take off. The clear way is
a threedimensional zone, clear of obstacles,
placed at runway's extremity, above the stopway,
in order to ease the take off. The clearway's
width must not be under 75 meters from the
runway's center line.
Regarding the so called declared distances
of a runway, we have the LDA (Landing Distance
Available) same as TORA (Take Off Run Available)
which are distances of the runway without
the stop way and the clear way, TODA (Take
Off Distance Available) which is the distance
of the runway plus the clearway, and the
ASDA (Accelerate Stop Distance Available)
which consists of runway's distance plus
the stopway.
The distance of the hold short from the center
line of the runway varies in accordance with
the type of runway: for non instrument runways
code number one the holding position is placed
at 30 meters, for runways code number two
is situated at 40 meters while for runways
code number three and four the hold short
is placed at 75 meters; for non precision
instrument runways code number one and two
the hold short is at 40 meters, while for
those which are code number three and four
is at 75 meters; for precision runways of
the first category code number 1 and 2 the
holding position is at 60 meters while for
runways code number 3 and 4 is at 90 meters;
for precision runways of the second category
and of the third category the holding position
is situated at 90 meters.
Written by Claudio Adriano Dobre, © 2005
Please notice that this article was written in 2005, so the contained information may be outdated.
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