Which components are monitored by the synoptic pages for the APU system and services?

The correct choice emphasizes the monitoring functions associated with the Auxiliary Power Unit (APU) system. The APU plays a crucial role in providing power and services when the main engines are not running.

The specific components that the synoptic pages monitor for the APU system are fuel, electrical, and environmental control systems (ECS).

• Fuel: The monitoring of fuel is essential since the APU requires fuel to operate. Ensuring the fuel levels, pressure, and flow rate are appropriate is critical for safe functioning.

• Electrical: The APU generates electrical power for the aircraft during ground operations. Monitoring the electrical output from the APU is vital to ensure that the aircraft systems that rely on this power are functioning properly.

• ECS: The environmental control system maintains cabin temperature and air pressure. Monitoring the ECS parameters linked to the APU ensures that passengers and crew are kept in a comfortable environment while the main engines are off.

The other options include combinations of hydraulic, pneumatic, and bleed-air systems, which are not the main focus of the APU's synoptic page monitoring. While hydraulic and pneumatic systems are important in the overall function of the aircraft, they are not directly related to the APU's