What is the primary function of the ground heat bus in the aircraft?

The primary function of the ground heat bus in an aircraft is to aid engine starts in cold weather. This system is specifically designed to provide the necessary heat to various components that can be adversely affected by extremely low temperatures. For instance, cold weather can lead to the thickening of lubricants and fluids, which can make engine starts challenging. By ensuring that critical components such as the fuel and oil systems are adequately warmed, the ground heat bus facilitates smoother engine operation during start-up.

While other functions like providing cockpit heating, warming batteries, and assisting ground power operations can be crucial in different contexts, they do not represent the main purpose of the ground heat bus. The ground heat bus is primarily implemented to ensure reliable engine starts, particularly in conditions where cold temperatures can hinder performance.