What is the approximate life of the standby battery?

The standby battery is designed to provide power for critical systems in the event of a main power failure or during specific operational conditions where power is essential. The approximate life of the standby battery being around 30 minutes is a common specification for many avionics systems. This duration is generally sufficient to allow pilots to manage critical flight operations and safely handle the situation until the main power source can be restored or alternative measures can be taken.

In practical terms, 30 minutes allows for adequate time for response without exceeding the limitations of most systems and instrumentation powered by the standby battery. This is especially important in ensuring the safety and control of the aircraft. During this time, pilots can rely on the essential instruments and navigation aids necessary for maintaining safe flight until a resolution to the power issue occurs.

The other options, while they might seem plausible, typically exceed the expected operational capacity of standby batteries in many systems. Hence, the established benchmark in aviation for such a situation is accurately reflected by the 30-minute estimate.