Which items are included in the hot battery bus?

The hot battery bus is a crucial component in an aircraft's electrical system, designed to provide power to certain electrical devices even when the aircraft is not actively started or in operation. This allows for specific systems to be powered at all times, which can be essential for safety and convenience.

In the context of this question, the items included in the hot battery bus typically consist of components that need constant electrical power for normal operation or for safety monitoring, regardless of the aircraft's status.

The correct answer includes a battery relay, entry lights, and ground heat. The battery relay is essential as it controls the flow of electrical current from the battery to other components, allowing them to function properly when needed. Entry lights are safety features that provide illumination at the aircraft doors, making it easier for passengers and crew to enter and exit, especially in low-light conditions. Ground heat refers to systems that provide heating to critical components, often during cold weather operations to ensure they function effectively.

Including these specific components supports the necessity of keeping certain systems operational and safe even when the aircraft is not powered by the main electrical bus, illustrating the purpose of the hot battery bus. Thus, the correct answer is cohesive and aligns with the functionality expected from the hot battery bus in aircraft systems