Airport Runway Location and Orientation
CEE 4674 Airport Planning and Design
Dr. Antonio A. Trani
Associate Professor of Civil Engineering
Virginia Tech
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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
Read Chapter 2 of FAA AC/150-5300-13 for more
information about each topic
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Runway Orientation and Wind
• 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
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Cross Wind Operations
All aircraft have maximum demonstrated cross wind
components (usually specified in the flight manual)
Wind vector
Crosswind Component
Aircraft Velocity
Vector
Runway
Wind vector
Resulting Aircraft
Ground Speed
Vector
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Demonstrated Wind Conditions
Each aircraft has a uniquely stated maximum crosswind
component (derived from flight test experiments)
• A Boeing 727-200 (approach group C) has a maximum
demonstrated wind component of 35 knots
• A cessna 172 (a single engine aircraft falling in approach
speed group A) has a maximum demonstrated crosswind
component of 17 knots
The challenge for the designer is to accommodate all of
the aircraft using the facility in a reliable and reasonable
manner
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Reporting Wind Conditions
Wind is reported on an azimuthal basis as shown below
w =15 knots North
(0o)
45o
West East
(270o) (90o)
o
Wind from 315
at 15 knots
South
(180o)
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Sample Crosswind Computation
γ
wc Crosswind
w component
Runway 27 wh
Wind vector
Headwind
component
wc = w sin (γ)
wh = w cos (γ) North
NOTE: Winds are always reported with
respect to the magnetic North
(in ATC transmissions)
East
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Crosswind Calculator (Appendix 1 of FAA
AC 150/5300-13)
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Design Criteria (FAA and ICAO)
Read Chapter 2 of FAA AC 150/5300-13 or Aerodrome
design manual (Volume 1 for ICAO standards)
Employ the most critical aircraft expected to operate in
the airfield (in this context the most critical is the largest
• 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
The argument of using the most critical aircraft might
sound counterintuitive (but it is necessary)
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FAA Crosswind Design Criteria
Recognizing that each aircraft has unique maximum
demonstrated crosswind characteristics the FAA (and
ICAO as well) set a low value for crosswind design
criteria
Airport Reference Code Design Crosswind Value (knots)
A-I and B-I 10.5
A-II and B-II 13.0
A-III, B-III and C-I through D-III 16.0
A-IV through D-IV 20.0
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ICAO Crosswind Design Criteria
Similar to the FAA criteria in many ways. However,
ICAO has two aerodrome classifications.
Aerodrome Runway Reference Runway Reference Field Length
Code (m.)
A < 800
B 800 - 1,200
C 1,200 - 1,800
D > 1,800
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ICAO Crosswind Design Criteria
Similar to the FAA criteria in many ways but simpler
(only three design values).
Runway Length (m.) Design Crosswind Value (knots)
< 1,200 10.0
1,200 - 1,500 13.0
> 1,500 20.0
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Data Sources
Collect wind data from a reliable source:
• National Oceanic and Atmospheric Administration (NOAA),
Environmental Data Service (EDS)
• The EDS's National Climatic in Asheville, North Carolina
• The wind data is usually available for hundreds of stations
across the U.S.
• Ironically, Blacksburg has a National Weather Service
station but EDS does not have a record of us!
• 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)
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Data Sources
• For mountainous terrain with data without wind data, the use
of nearby stations is of questionable value
• Take one year of wind data if possible
• Several automated reporting systems exist at airport that can
be used for this purpose (EDS will not have data about
these)
AWOS - Automated Weather Observation System
• The data available from NOAA usually includes 10-15 years
(daily observations)
• Use 5-10 years of data for airport planning purposes (except
when you are collecting the data yourself)
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Sample Wind Data
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Wind Rose Analysis
• A clever way to portray all wind data in agraphical template
and estimate the percent runway coverage
• The wind rose is just a graphical way to add decompose
vectors
• The wind rose is populated with percentages derived from
wind observations
• You can build a wind rose with a piece of cardboard and a
transparent template
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Wind Rose Template
Enter percentages Each cell
represents
in each cell a wind direction
and magnitude
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Sample Wind Rose with Data
84.1%
winds
< 10 knots
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Wind Rose and Template
Runway
orientation
shown is
105-285o
About
2.72% of
time
winds
exceed 13 knots
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Use of FAA Computer Program (AD42.exe)
The FAA computer program companion to the AC
5300-13 can be used to study runway orientation
coverages
It requires a text file in a very specific format that
contains number of wind observations from various
azimuths and winds speeds (similar to the wind rose
template)
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Sample Data for Computer Program
Used
for 2
runway
ends
Wind Speeds
Azimuth (x 10)
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Sample Output of AD42.exe Program
Sample Crosswind
runway
result
for
2 runways
Primary
runway
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Sample Analysis for One Runway End (5-
knot tailwind component allowed)
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Single Runway End Analysis
Runway End
110o can be
used 80.4% of time
(allows 5-knot tailwind)
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