A runway excursion—when an aircraft runs off the runway during takeoff, landing, or taxiing—is one of the more serious safety incidents in aviation. While runway excursions are rare, they can be dangerous due to the potential for aircraft damage, injury to passengers and crew, and disruption to airport operations. In this article, we explore the causes of runway excursions, what happens when a plane runs off the runway, the risks involved, and how aviation professionals and airport infrastructure work to prevent these incidents.
What is a Runway Excursion?
A runway excursion occurs when an aircraft veers off the side or end of the runway during its takeoff or landing sequence. Runway excursions can happen for various reasons, including pilot error, weather conditions, mechanical failures, or runway surface issues. Excursions are categorized based on whether they occur during takeoff or landing, and whether the plane ends up going off the side (lateral excursion) or overruns the end of the runway (overrun).
Causes of Runway Excursions
Runway excursions are generally the result of a combination of factors, often involving both human and environmental conditions. Below are some of the most common causes:
Weather Conditions
Weather is one of the most significant factors contributing to runway excursions. Adverse weather conditions, such as wet, icy, or snowy runways, can reduce the available friction between the plane’s tires and the runway surface. This can cause the aircraft to skid, lose traction, or fail to decelerate properly during landing.
- Wet or flooded runways: Water on the runway can lead to hydroplaning, where the aircraft’s tires lose contact with the surface, increasing the risk of loss of control.
- Ice and snow: Reduced traction on icy or snowy runways can make it harder for the aircraft to stop after landing, increasing the likelihood of an overrun.
- Crosswinds: Strong or gusty crosswinds can push the aircraft off centerline during landing, making it harder for pilots to maintain control on the runway.
Pilot Error
Pilot error, such as improper speed management, incorrect landing approaches, or delayed decision-making, is another leading cause of runway excursions. A few examples include:
- Late or incorrect decision to abort landing: If a pilot doesn’t decide to abort the landing in time (known as a go-around), the plane might land too far down the runway and run out of space.
- Incorrect approach speed: A plane approaching too fast or too slow can result in poor control during landing, particularly in challenging conditions.
Mechanical Failure
A mechanical failure in the aircraft’s systems—such as the brakes, steering mechanisms, or landing gear—can cause the aircraft to lose control during the landing or takeoff roll. For example, brake failure or loss of hydraulic power can prevent the aircraft from decelerating effectively, leading to an overrun.
Runway Conditions and Infrastructure
The runway surface itself can also contribute to runway excursions. Issues such as poor runway maintenance, potholes, or uneven surfaces can cause a plane to lose traction, affecting its ability to stop or stay on course. Additionally, runways that lack sufficient Runway Safety Areas (RSAs) or End Safety Areas (RESAs) increase the risk of significant damage or injury if an aircraft runs off the runway.
Overloaded Aircraft
An aircraft that is too heavy or improperly balanced may require more distance to take off or land. An overloaded plane may struggle to decelerate properly during landing, increasing the chance of an overrun. Additionally, improper weight distribution could affect the aircraft’s handling characteristics.
What Happens When a Plane Runs Off the Runway?
When an aircraft runs off the runway, the consequences can range from minor damage to catastrophic outcomes, depending on several factors, including the speed at which the plane is moving, the runway’s surrounding environment, and the effectiveness of emergency response teams. Here’s what typically happens in a runway excursion:
1. Aircraft Movement and Impact
If a plane leaves the runway, its movement is typically slowed, but it can still travel a considerable distance depending on its speed and the runway’s surface conditions.
- Lateral Excursion: When a plane runs off the side of the runway (known as a lateral excursion), it may collide with objects such as airport signs, lighting, fences, or ground equipment. This can cause significant damage to the aircraft’s wings, fuselage, or undercarriage.
- Overrun: If the aircraft overruns the end of the runway (known as a runway overrun), it may continue into a Runway Safety Area (RSA) or even beyond into undeveloped terrain or an airport perimeter fence. This can cause the aircraft to stop abruptly, potentially resulting in serious damage or injury.
Conclusion
Runway excursions, though rare, are serious events that can have significant consequences for aircraft, passengers, and airport operations. They can occur due to various factors, including adverse weather, pilot error, mechanical failure, or runway conditions. When a plane runs off the runway, it can lead to loss of control, injury, or even a crash, which is why safety measures such as proper runway design, advanced aircraft systems, and well-trained crews are essential in preventing these incidents.
