When the APU is started, the APU Generator will automatically connect to the electrical system and cause the Engine Generators to disconnect.

When the APU is started, the APU Generator will automatically connect to the electrical system and cause the Engine Generators to disconnect.

• A. True
• B. False
• C. The APU connects but the Engine Generators stay connected
• D. The Engine Generators disconnect but the APU does not connect

Answer: (B)

When the APU starts, its generator is designed to connect to the electrical network to supply power, enabling the aircraft to operate with or without external power. But the engine generators do not automatically disconnect just because the APU has connected. In normal parallel operation, the APU and the engine generators can share the electrical load, with load sharing managed by the electrical power control system. The engine generators would only disconnect if a fault occurs, or if a generator is manually turned off or isolation logic trips it, not simply due to the APU starting.

When the APU starts, its generator is designed to connect to the electrical network to supply power, enabling the aircraft to operate with or without external power. But the engine generators do not automatically disconnect just because the APU has connected. In normal parallel operation, the APU and the engine generators can share the electrical load, with load sharing managed by the electrical power control system. The engine generators would only disconnect if a fault occurs, or if a generator is manually turned off or isolation logic trips it, not simply due to the APU starting.