The standby system provides backup for which cockpit indication when hydraulic B fails?

• A. LEDs
• B. Flaps
• C. Spoilers
• D. Fuel gauge

Answer: (A)

Standby power is there to keep essential cockpit indications alive when a primary system loses power, so the crew can still understand what’s happening. In this case, the standby system powers the cockpit warning lights—LED indicators—that show the status of hydraulic systems. When hydraulic B fails, those LEDs continue to illuminate or indicate the fault, giving the pilots a clear, visible alert to the problem.

Flaps and spoilers are driven by hydraulics, and their actual movement isn’t about indicating status through a backup light—their operation depends on the hydraulic system itself. The fuel gauge is unrelated to hydraulic status and is not typically a function backed up by the standby power in this context. So the LED indicators are the cockpit indication that the standby system reliably preserves.