Is the APU Serv Bus button preflighted on the CRJ 700/900?

The APU Serv Bus button is not preflighted on the CRJ 700/900, meaning that it does not undergo a routine check as part of the preflight procedures. This button is specifically used to control the Auxiliary Power Unit (APU) service bus, which provides electrical power when the APU is running.

In the context of preflight checks, certain systems and components are verified to ensure the aircraft is safe and ready for flight. However, the APU Serv Bus functionality is not one of those routinely checked before every flight. Its status is typically evaluated only when operational needs for the APU arise, or during maintenance checks, when detailed inspections of systems like the APU are performed comprehensively.

Understanding the operational requirements of the aircraft is key, as aircraft systems are designed to ensure safety while balancing the needs for maintenance and functionality checks during various phases of the aircraft’s use, including preflight and maintenance activities.