How long can the main battery typically power items on the main battery bus?

The main battery of the T-6A is designed to provide power to essential systems on the main battery bus for a minimum of 30 minutes. This duration is important for several reasons: it ensures that critical avionics and electrical systems remain operational in the event of an engine failure or when external electrical power is not available. The ability to sustain power for this timeframe allows pilots to maintain control of the aircraft, communicate with air traffic control, and manage other systems, which is crucial for safety and operational effectiveness during flight.

When considering the other options, it's clear that 15 minutes would likely not provide sufficient time in an emergency to secure the necessary operational control, while 45 minutes could suggest a battery capacity that exceeds the actual design for typical operational use. "Indefinitely until recharged" is also inaccurate, as batteries have limitations in their discharge capabilities and require recharge after depletion. Hence, the specification of a minimum of 30 minutes highlights the reliability built into the aircraft’s design for managing power needs safely.