What does the APU control panel indicate during normal operation?

During normal operation of the Auxiliary Power Unit (APU) in the C-130J, the APU control panel provides vital information about the operational status of the unit. It displays parameters such as RPM (revolutions per minute), temperature, and fuel level.

Monitoring RPM is crucial as it indicates how efficiently the APU is running and whether it is maintaining the required power output. The temperature readings help ensure that the APU is operating within safe thermal limits, preventing overheating and potential damage to the unit. Additionally, the fuel level indication is important for understanding how much fuel is being consumed and how long the APU can continue to operate before refueling is necessary.

The other options do not encompass the full spectrum of information provided by the APU control panel. Fuel consumption is a vital aspect, but it's not the only factor monitored during operation. Air pressure levels are relevant but are not the primary indicators shown on the control panel. Similarly, while electrical output is important, it is not the sole focus of the APU operation metrics. The combination of RPM, temperature, and fuel level gives a comprehensive overview of the APU's health and functionality, making it critical for safe operations and effective performance management.