Which formula is used to determine where to position the mobile aircraft arresting system on the runway edge?

The correct formula for determining the position of the mobile aircraft arresting system on the runway edge involves considering the necessary safety and operational factors. The use of "pendant length + 15 feet" ensures that there is a sufficient buffer zone beyond the actual pendant length of the arresting system. This additional distance accounts for variations in aircraft landing dynamics and ensures ample room for the system to function effectively without interfering with runway operations or posing a safety risk.

In scenarios with mobile aircraft arresting systems, it's crucial to maintain a balance between effective system deployment and safety margins. The 15-foot addition is specifically calculated based on operational standards that guide the placement for optimal arresting system performance while minimizing risk. This helps to guarantee that the aircraft has a safe area to come to a halt if necessary without overextending into areas that could lead to accidents or runway obstructions.