What is RESA in Aviation? (Runway End Safety Area)

In aviation, the term “Runway End Safety Area” (RESA) refers to a designated area beyond the runway thresholds that provides an additional margin of safety in the event of an aircraft runway overrun or undershoot. RESA is an important aspect of airport design and plays a crucial role in mitigating the potential risks associated with runway accidents.

The Importance of Runway End Safety Area

The main purpose of a Runway End Safety Area is to provide a clear, obstacle-free zone for an aircraft in case it fails to stop or land within the confines of the runway surface. It acts as a buffer zone to help decelerate and safely stop an aircraft that has overrun the runway. The RESA is designed to be wide enough to accommodate an aircraft and minimize the likelihood of injury to passengers or significant damage to the aircraft itself.

According to the International Civil Aviation Organization (ICAO), the recommended minimum length for a RESA is 90 meters (295 feet) at the end of paved runways and 240 meters (787 feet) at the end of unpaved runways. This length is considered adequate to reduce the risks associated with runway overruns or undershoots. However, it’s important to note that different countries may have their own regulations and standards regarding RESA length and design.

Runway end safety areas are particularly critical for runways located near bodies of water, deep ravines, or areas with hazardous obstacles. They provide a measure of protection in scenarios where an aircraft loses control during landing or takeoff and veers off the runway surface. Without a RESA, the consequences of such incidents could be catastrophic.

A key factor in the design and positioning of RESAs is the runway’s approach slope. A proper RESA should be situated in a way that allows an aircraft to safely decelerate without encountering any undue obstacles. The slope of the RESA must not exceed a certain gradient to ensure that it does not compromise the aircraft’s ability to come to a controlled stop.

The Design and Characteristics of RESAs

Runway end safety areas are designed with specific characteristics to ensure their efficiency in protecting aircraft and passengers during runway overruns or undershoots. Some key features of RESAs include:

1. Length and Width: As mentioned earlier, the recommended length of a RESA is 90 meters (295 feet). However, it should be noted that longer RESAs provide enhanced safety margins. The width of a RESA depends on various factors, including the runway’s width, visibility conditions, and approach slope.

2. Surface Material: The surface of a RESA is usually made of natural materials, such as soil or grass. This allows for better deceleration and minimizes the potential for structural damage to the aircraft. However, paved RESAs are becoming more common, especially in areas with challenging terrain or high traffic volume.

3. Grading and Drainage: RESAs are designed to have a smooth grading, allowing for effective deceleration without causing abrupt changes in momentum. They also incorporate proper drainage systems to prevent the accumulation of water or debris, which could affect the aircraft’s performance during a runway overrun.

4. Markings and Lighting: To enhance visibility and awareness, RESAs may be marked with appropriate signage and lighting. These may include yellow chevrons, which indicate the beginning of the RESA, and edge lights to outline the area’s boundaries. Clear markings help pilots and ground personnel recognize the RESA and make informed decisions during emergency situations.


Runway End Safety Areas (RESAs) are an essential component of aviation infrastructure. They provide an additional margin of safety, reducing the risks associated with runway overruns or undershoots. A properly designed and maintained RESA can effectively protect aircraft and passengers, minimizing the likelihood of severe accidents or injuries.

As aviation continues to evolve, RESA standards and regulations will also evolve, keeping pace with technological advancements and best practices. It is essential for airport authorities and aviation organizations to prioritize runway safety and invest in the design and maintenance of RESAs to ensure the highest level of safety for all stakeholders involved.

For more information on runway safety and airport infrastructure, visit the ICAO website.

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