What is required for the RSA according to regulations?

The requirement for the Runway Safety Area (RSA) according to regulations focuses on the area being "fixed by function and frangible." This means that the RSA must be free from obstructions that could pose a risk to aircraft and must contain features that do not create additional hazards in the event of an aircraft accident. The primary function of the RSA is to enhance safety by providing a buffer zone around the runway, which can help in reducing the severity of accidents.

Being "frangible" refers to the ability of objects within the RSA to break away or collapse under impact, minimizing damage to the aircraft. While aspects like the surface material, location, and lighting can certainly contribute to the overall safety and effectiveness of the RSA, the fundamental regulatory requirement is centered on the designated status of being fixed for function and frangible in nature.

This understanding helps clarify why the other options may not align with regulatory standards. For instance, a specific surface material such as asphalt is not mandated in regulations, nor is a particular location like the midpoint of the runway needed. Additionally, while lighting can be beneficial for visibility, it is not a strict requirement dictated by regulations for the RSA.