Runway Location Considerations







The following factors should be considered in
locating and orienting a runway:
Wind
Airspace availability
Environmental factors (noise, air and water
quality)
Obstructions to navigation
Air traffic control visibility
Wildlife hazards


The orientation of the runway is an important
consideration in airport planning and design
The goal of this exercise is to define the
runway orientation that maximizes the
possible use of the runway throughout the
year accounting for a wide variety of wind
conditions



FAA and ICAO regulations establish rules
about runway orientation and their expected
coverage
Ideally, all aircraft operations on a runway
should be conducted against the wind
Unfortunately, wind conditions vary from hour
to hour thus requiring a careful examination
of prevailing wind conditions at the airport site
Design criteria


Provide a runway (or runways) orientation
that satisfies 95% coverage (i.e., crosswinds
below a critical value) considering yearly wind
conditions
If one runway does not meet the 95% criteria
design a second crosswind runway
Data Source




Carefully use weather record from two or more
nearby stations if wind data is not readily available
at the proposed airport site (be very careful of local
weather effects)
For mountain terrain with data without wind data, the
use of nearby stations is of questionable value.
Take one year of wind data if possible.
Use 5-10 years of data for airport planning purposes
(except when you are collecting data yourself.)
How to use WIND ROSE for determining
the Runway Orientation


Optimum runways directions can be
determined from the wind rose by the use of
a strip of transparent material on which three
parallel and equally spaced lines have been
plotted.
The middle line represents the runway center
line and the distance between this line &
each outside line is, to scale, equal to
allowable cross wind component
wind rose graphically depicts wind velocities,
directions, and their probability of occurrence in
a format resembling a compass.The radii of the
concentric circles arc scaled to represent wind
velocities of 4, 13, 25, 32, and 47 mph. Each
direction subtends an angle of 22.5 degrees.
How to use WIND ROSE for determining
the Runway Orientation


The transparent strip is placed over the wind
rose in such a manner that the center line on
the strip passes through the center of the
wind rose.
With the center of the wind rose as pivot
point, the transparent overlay is rotated until
the sum of the percentage included between
the outside line is a maximum.
How to use WIND ROSE for determining
the Runway Orientation



The next step is to read the bearing for the
runway on the outer scale of the wind rose
where the center line on the transparent strip
crosses the direction scale. True north is
used for designating the bearing.
The next step is to examine wind data during
restricted visibility conditions cited previously.
Plot a wind rose for this condition.

From this analysis it can be analyzed that
whether the runways are capable of
accepting planes at 95% of the time when
restricted visibility conditions prevails.