When do the B pumps turn on in AUTO mode?

When do the B pumps turn on in AUTO mode?

• A. When the appropriate bus is powered
• B. When the flaps are not at 0 degrees
• C. When at least one IDG is online
• D. When the engine is at idle

Answer: (A)

In AUTO mode, the B pumps respond to electrical power availability rather than mechanical signals. They turn on when the corresponding B hydraulic bus is energized. If that bus isn’t powered, the pumps won’t start, even if hydraulic demand exists elsewhere. This keeps the pumps operating only when there’s power to drive them, providing automatic control and proper power budgeting. The other factors listed (flap position, IDG status, engine idle) don’t directly trigger the B pumps in AUTO; they may influence hydraulic demand in other systems, but the actual auto-start condition is the presence of power on the B bus.

In AUTO mode, the B pumps respond to electrical power availability rather than mechanical signals. They turn on when the corresponding B hydraulic bus is energized. If that bus isn’t powered, the pumps won’t start, even if hydraulic demand exists elsewhere. This keeps the pumps operating only when there’s power to drive them, providing automatic control and proper power budgeting. The other factors listed (flap position, IDG status, engine idle) don’t directly trigger the B pumps in AUTO; they may influence hydraulic demand in other systems, but the actual auto-start condition is the presence of power on the B bus.