What happens when aircraft land overweight?

Weight and stopping distance

The stopping distance of an aircraft is directly affected by its weight. An overweight aircraft has more inertia and requires a greater distance to come to a complete stop. The use of reverse thrust and brakes must be optimized to handle this increased stopping distance. Pilots also have to be mindful of the runway length and condition; for instance, a wet or icy runway might further impede braking effectiveness and require even more distance for a safe stop.

Braking

The higher landing speed increases the stress on the tires and brakes, which can lead to higher wear and risk of failure if not managed correctly. Pilots must ensure that the braking is done steadily and evenly to prevent potential blowouts or skidding, and use the brake fans appropriately.

Brake fans are designed to cool the brakes of an aircraft after landing, a time when the brakes can reach extremely high temperatures due to the friction generated in slowing and stopping the aircraft. The use of brake fans helps to prevent overheating, which can lead to brake wear or even failure. They are installed as part of the aircraft’s landing gear system, specifically around the brake assemblies. When activated, these fans blow air directly onto the brakes, enhancing the natural cooling process by increasing the rate of heat dissipation. This forced-air cooling is crucial because it reduces the time it takes for the brakes to cool to a safe temperature, allowing the aircraft to be ready for another flight sooner.

Brake fans are typically used in situations where an aircraft has to perform quick turnarounds, such as in busy commercial airports. They are also crucial when an aircraft lands with high kinetic energy, such as in the case of an overweight landing. In these scenarios, the brakes work harder and thus generate more heat. Additionally, in hot weather conditions, the ambient temperatures can impede the natural cooling of the brakes, making the role of brake fans even more significant.