How long can the standby battery supply power to the STBY BUS?

How long can the standby battery supply power to the STBY BUS?

• A. 90 minutes
• B. 180 minutes
• C. 120 minutes
• D. 240 minutes

Answer: (B)

The standby power system is designed to keep the essential flight instruments alive when normal electrical power is lost. The STBY BUS carries the critical data and indicators the crew needs to maintain control and situational awareness, such as attitude, air data, and basic flight information, during an electrical failure. In this aircraft, the standby battery is sized to supply that STBY BUS for 180 minutes. That three-hour endurance gives crews a practical window to recognize the loss, continue the flight with the remaining loads, and establish an alternative power source or complete the diversion as needed. Shorter durations (90 or 120 minutes) would risk losing power too soon, while a longer duration (240 minutes) isn’t what the system is specified to provide.

The standby power system is designed to keep the essential flight instruments alive when normal electrical power is lost. The STBY BUS carries the critical data and indicators the crew needs to maintain control and situational awareness, such as attitude, air data, and basic flight information, during an electrical failure.

In this aircraft, the standby battery is sized to supply that STBY BUS for 180 minutes. That three-hour endurance gives crews a practical window to recognize the loss, continue the flight with the remaining loads, and establish an alternative power source or complete the diversion as needed. Shorter durations (90 or 120 minutes) would risk losing power too soon, while a longer duration (240 minutes) isn’t what the system is specified to provide.