Have you ever wondered why the runways at airports where airplanes take off and land are only at certain angles and directions? Designing an airport from start to finish is a serious engineering endeavor that involves many variables. Prior to the construction of the runways, which are one of the most basic and important components of the airport, the location, number, length and layout of the runways are determined by taking into account the conditions set by the authorized institutions in the field of aviation.
Conditions Effective in Determining the Location, Number and Length of Runways:
● Weather-Meteorological conditions, wind distribution and fog formation. In particular, the direction of the main runway should be arranged in the direction of the prevailing wind, subject to the availability of other factors. The issue of the direction of the prevailing wind, which came to the fore after Istanbul Airport was put into operation, is an example that emphasizes the importance of meticulous calculation of meteorological conditions in runway construction.
● Topography of the airport site and surrounding area. When determining the direction of all runways, it is very important that there are no obstacles in front of the approach and departure areas. The direction of the runway should be arranged in such a way that aircraft are not diverted to crowded areas and fields.
● Type and density of air traffic and characteristics of air traffic control. The number of runways is determined by taking into account the peak periods of air traffic. Considering the number of aircraft landings and take-offs in an hour and the types of aircraft, it is necessary to ensure that the number of runways is sufficient to meet the air traffic demand.
● Performance characteristics of the aircraft that will land on the runway. The length of the runway in particular is directly linked to this factor, as aircraft types differ in landing and take-off distances.
● Environmental conditions, especially noise. The impact of the location and alignment of the runway on wildlife and the overall ecological balance in the region are among the factors to be considered. Another issue is the presence of noise-sensitive residential areas in the vicinity.
Once all the above conditions and many more details have been taken into account, it remains to decide on the type and number of runways. Depending on the needs and conditions, a single runway may be sufficient, while large airports may have multiple runways intersecting each other at certain angles or parallel to each other.
How Many Types of Runway Surfaces Are There?
According to the material they are built with; the runways are divided into two as soft and paved runways. A soft runway is one in which the surface on which aircraft take off and land is not fixed with any hardened material. Soft runways are often used in places where the construction and maintenance of runways is very difficult. Compacted sand, gravel, dirt surfaces, old lake beds, specially turfed fields, even snow and ice-covered areas in the polar regions are included in the soft track category. Take-offs and landings on such runways, which change shape over time because their surfaces are not stable and are considered “dirty”, require special training and can lead to dangerous situations.
Which Materials are Used in Airport Runway Construction?
A paved runway is defined as a hard-surfaced, high-safety and long-lasting runway built for large passenger aircraft used in civil air transportation. Although asphalt and concrete are widely preferred in the construction of such runways, which are smooth, smooth and durable, in some cases metal layers can also be used to increase strength. Although their surfaces can cause dangerous situations in conditions of icing, snowfall and precipitation, the maintenance, upkeep and repair of such runways, which are quite safe under normal conditions, are just as expensive and difficult. A “clean runway” is a runway that is free of foreign and unwanted objects, cracks, slopes, dents and ridges, and whose pavement (even if damp) meets the brake values shown in the aircraft’s performance certificate. In order for a runway to be considered clean, the amount of water, mud, snow and ice on it must be below the values permitted under aviation rules and regulations.