Types Of Runway Configurations, Marking And Safety

This Article Covers Various Types Of Runway Configurations And Their Combinations One By One.

Types Of Runway

Before Going With Types Of Runway Configurations Let Us See What Is Runway?

Runway

A runway is a rectangular area on the airport surface prepared for the takeoff and landing of aircraft. An airport may have one runway or several runways which sited, oriented, and configured in a manner to provide for the safe and efficient use of the airport under a variety of conditions.

Several of the factors which affect the location, orientation, and number of runways at an airport include local weather conditions, particularly wind distribution and visibility, the topography of the airport and surrounding area, the type and amount of air traffic to serviced at the airport, aircraft performance requirements, and aircraft noise.

Runway Configurations

The term runway configuration refers to the number and relative orientations of one or more runways on an airfield. Many runway configurations exist.

Most configurations are combinations of several basic configurations.

The basic configurations are

Single runways,
Parallel runways,
Intersecting runways, and
Open-V runways.

Single Runway

It has estimated that the hourly capacity of a single runway in VFR (visual flight rules) conditions is somewhere between 50 and 100 operations per hour, while in IFR (instrument flight rules) conditions this capacity reduced to 50 to 70 operations per hour, depending on the composition of the aircraft mix and navigational aids available.

Parallel Runways

The capacities of parallel runway systems depend on the number of runways and on the spacing between the runways.

Two, three, and four parallel runways are common.

The spacing between parallel runways varies widely. For the purpose of this discussion, the spacing is classified as close, intermediate, and far, depending on the centreline separation between two parallel runways.

Close parallel runways spaced from a minimum of 700 ft (for air carrier airports) to less than 2500 ft. In IFR conditions an operation of one runway is dependent on the operation of other runway.

Intermediate parallel runways spaced between 2500 ft to less than 4300 ft.

IFR Condition

In IFR conditions an arrival on one runway is independent of a departure on the other runway.

Far parallel runways spaced at least 4300 ft apart. If the terminal buildings placed between parallel runways, runways always spaced far enough apart to allow room for the buildings, the adjoining apron, and the appropriate taxiways.

When there are four parallel runways, each pair spaced close, but the pairs spaced far apart to provide space for terminal buildings.

In VFR conditions, close parallel runways allow simultaneous arrivals and departures, that is, arrivals may occur on one runway while departures are occurring on the other runway.

Aircraft operating on the runways must have wingspans less than 171 ft for centreline spacing at the minimum of 700 ft. The hourly capacity of a pair of parallel runways in VFR conditions varies greatly from 60 to 200 operations per hour depending on the aircraft mix and the manner in which arrivals and departures processed on these runways.

Similarly, in IFR conditions the hourly capacity of a pair of closely spaced parallel runways ranges from 50 to 60 operations per hour, of a pair of intermediate parallel runways from 60 to 75 operations per hour, and for a pair of far parallel runways from 100 to 125 operations per hour.

Intersecting Runways

Many airports have two or more runways in different directions crossing each other.

These are referred to as intersecting runways.

Intersecting runways are necessary when relatively strong winds occur from more than one direction, resulting in excessive crosswinds when only one runway is provided.

When the winds strong, only one runway of a pair of intersecting runways can used, reducing the capacity of the airfield substantially. If the winds relatively light, both runways can used simultaneously.

The capacity of two intersecting runways depends on the location of the intersection (i.e., midway or near the ends), the manner in which the runways operated for takeoffs and landings, referred to as the runway use strategy, and the aircraft mix.

The farther the intersection is from the takeoff end of the runway and the landing threshold, the lower is the capacity.

The highest capacity achieved when the intersection is close to the takeoff and landing threshold.

Open-V Runways

Runways in different directions which do not intersect are referred to as open-V runways. Like intersecting runways, open-V runways revert to a single runway when winds are strong from one direction.

When the winds light, both runways may used simultaneously. The strategy which yields the highest capacity is when operations are away from the V and this is referred to as a diverging pattern.

In VFR the hourly capacity for this strategy ranges from 60 to 180 operations per hour, and in IFR the corresponding capacity is from 50 to 80 operations per hour.

When operations toward the V it is referred to as a converging pattern and the capacity is reduced to 50 to 100 operations per hour in VFR and to between 50 and 60 operations per hour
in IFR.

Combinations of Runway Configurations

From the standpoint of capacity and air traffic control, a single-direction runway configuration is most desirable.

All other things being equal, this configuration will yield the highest capacity compared with other configurations. For air traffic control the routing of aircraft in a single direction is less complex than routing in multiple directions.

Comparing the divergent configurations, the open-V runway pattern is more desirable than an intersecting runway configuration.

In the open-V configuration an operating strategy that routes aircraft away from the V will yield higher capacities than if the operations reversed.

If intersecting runways cannot avoided, every effort should made to place the intersections of both runways as close as possible to their thresholds and to operate the aircraft away from the intersection rather than toward the intersection.

Naming Of Runway

Runway are named by a number between 01 and 36, which generally the magnetic azimuth of the runways heading in decadegrees.

This heading differs from true north by the local magnetic declination.

A runway can normally used in both directions and named for each direction separately.

Runway Marking

The area marked with yellow chevrons (V shapes) are the blast pads, also referred to as overrun areas or stop ways.

These areas often constructed before start of a runway to reduce the erosion of earth by the jet blast produced by large planes when they power up for take-off.

Blast pads often not as strong as the main paved surface of the runway and aircraft not allowed to use it except in extreme emergencies.

The threshold essentially the start or end of the actual runway itself.

the touch down zone is the target area for pilots to stick the wheels of their aircraft on the runway.

Runway Safety

Types of runway safety incidents include:-

Runway Excursion– An Incident Involving only a single aircraft, where it makes an inappropriate exit from runway.

Runway Overrun– A type of excursion where the aircraft unable to stop before the end of runway.

And Runway Incursion– An incident involving incorrect presence of vehicle, person or another aircraft on the runway disaster.

Runway Confusion– An aircraft makes use of the wrong runway for landing or takeoff.

Runway Undershoot– An aircraft that lands short of the runway.

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Ketan Pattekar

Author & Editor Of This Blog.

Founder Of “KPSTRUCTURES”