Most of the world’s airports’ infrastructure is outdated, because it was built several decades ago, based on the aircraft fleet, traffic intensity and safety measures suited to the time when the airport was built. Since the aircrafts have increased, the last decades, in both weight and speed, the runway safety margins have therefore consequently decreased.
Example of development from 1950 to 2020:
- Demands on airports has gradually increased over time
- In 1950 a DC 3 had a weight of 11.000 kg carrying 30 passengers landing in 90 knots
- Today a A330 has a weight of 230.000 kg carrying 300 passengers landing in 140 knots
- Despite modern systems the need for runway safety requirements have increased with a factor of x3+
Basic facts – runway safety
Runway excursions are the most common type of aviation accidents worldwide representing 22% of all accidents. The reasons behind many of these accidents are either pilot errors (not following SOP, landing late or landing at high speed), mechanical failures (brake malfunction), weather (wind, contamination of pavement), sabotage or other examples of human errors.
Runway Excursions – what is it?
According to ICAO, a runway excursion is a veer off or overrun off the runway surface. This means when the wheels of an aircraft on the runway surface depart the end (overrun) or the side (veer-off) of the runway surface, which can occur at take-off or landing.
Statistics of Runway Excursions:
- Runway excursions costs exceed $900 million per year
- Runway overruns account for more than 50% of runway excursions
- Non-compliance RESA’s create risk to passengers, airports, airlines and the general public
- EMAS is the safest option for meeting ICAO RESA requirements when there is a non-compliant RESA
In case of a runway overrun, there could be severe consequences depending on when and where the aircraft get to a stop. Some runways are built dangerously close to the sea, rivers, cliffs, roads or other obstacles and in these cases an overrun can lead to catastrophic consequences such as fatalities or severe injuries to passengers and crew. And not to mention damage to the aircraft and to the airfield installations, leading to costly delays and damaged airline and airport reputation.
Passive Safety is important
No matter which active systems the aircrafts have installed and what procedures the pilots shall follow, passive safety systems are still necessary. When comparing driving a top modern car, with active safety systems, on a mountain road close to a cliff without any safety precautions, or choosing to drive the same car on a road with safety railings, the choice is rather clear.
Mitigate the severity of runway excursions
The surface surrounding the runway prepared or suitable for reducing the risk of damage to airplanes in the event of an undershoot, overshoot, or excursion from the runway is called Runway Safety Area. A good and reliable area at the end of runways, a Runway End Safety Area (RESA), is the best way of mitigating impact in case of an excursion of an aircraft. Most runways have enough area for a sufficient RESA, stopping an aircraft at 70 knots within 300 meters from the end of the runway (ICAO recommendation). If there are space limitations and reduction of the runway’s declared distances or a geographical extension is not possible, an EMAS (Engineered Material Arresting System) is the option.
FAA runway safety
The Federal Aviation Administration (FAA) is responsible for overseeing aviation safety in the United States, including the safety of runways at airports across the country. FAA runway safety is a critical aspect of aviation safety, as runway incidents can be catastrophic.
The FAA has implemented various measures to enhance runway safety, including the implementation of advanced technologies and the implementation of safety management systems. In addition, the FAA works closely with airport operators and other aviation stakeholders to identify and address runway safety issues. This includes conducting safety assessments, identifying, and mitigating risks, and promoting best practices for runway safety.
Despite these efforts, runway safety remains a significant concern in the aviation industry. The FAA continues to prioritize runway safety and is committed to working with stakeholders to develop new and innovative solutions to enhance safety and reduce the risk of runway incidents.
Runway safety area
Runway safety area (RSA) is a defined area surrounding a runway that is specifically designated to enhance the safety of aircraft operations. The RSA is designed to provide a clear area free of obstacles or hazards to minimize the risk of damage to an aircraft in the event of an overrun, undershoot, or excursion from the runway.
The FAA has set standards for the dimensions of RSA, which are based on the size of the aircraft that use the runway. The dimensions of RSA are measured in feet and depend on the width and length of the runway, as well as the approach speed of the aircraft.
It’s worth noting that the FAA also requires that the RSA be clear of any obstacles, such as buildings, trees, or other structures, that could pose a safety hazard to aircraft.
EMAS systems are typically installed at the end of a runway, beyond the runway safety area. EMAS systems are designed to provide an additional layer of safety for aircraft in the event of an overrun or undershoot. They have been successfully used in incidents where aircraft have overshot the end of the runway, preventing potentially serious accidents. Having an EMAS installed can potentially save lives and prevent significant damage to aircraft and airport infrastructure.
Runway Safety area dimensions
Runway safety area dimension refers to the minimum size requirements for the Runway Safety Area (RSA), which is an area surrounding the runway that is intended to provide a buffer zone for aircraft during takeoff and landing.
The dimensions of the RSA are determined by several factors, including the type of aircraft that use the runway, the approach and departure speeds of the aircraft, and the length and gradient of the runway. The International Civil Aviation Organization (ICAO) and national aviation authorities provide guidelines and regulations for the minimum dimensions of the RSA. The International Civil Aviation Organization (ICAO) recommends that all runways have a minimum RSA of 90 meters beyond each end of the runway and extending 150 meters beyond the end of the runway.
In addition to the RSA, other safety areas may be required, depending on the specific airport and the type of aircraft that use the runway. For example, an Engineered Material Arresting System (EMAS) may be used in some airports as an alternative to the RSA.
Overall, the size and dimensions of the RSA and other safety areas are designed to provide a safe stopping distance for aircraft during takeoff and landing, reducing the risk of accidents and ensuring the safety of passengers and crew.