What type of power does the APU generator typically generate?

The APU generator typically generates 28 volts DC electrical power, which is standard for many aircraft systems. This DC output is crucial for powering essential systems such as avionics, lighting, and other electrical components while the aircraft is on the ground or during flight, especially when the main engines are not operating.

The reason 28 volts DC is preferred is due to its efficiency in delivering reliable power to the aircraft's electrical systems. This voltage level allows the APU to effectively supplement the main power systems and maintain functionality across various systems necessary for aircraft operations, especially during startup or when auxiliary power is needed before the engines are started.

While alternatives like 120 volts AC or lower voltage DC options exist in different contexts, they do not align with the standard requirements and operating conditions of the APU in the C-5 aircraft. Understanding the APU's output ensures proper maintenance, troubleshooting, and operational use of the unit within the broader electrical system of the aircraft.