What unique feature distinguishes the fuel system operation in the Cirrus from that of the Arrow?

The unique feature that distinguishes the fuel system operation in the Cirrus from that of the Arrow is that the electric fuel pump serves as a backup only. In the Cirrus aircraft, the primary fuel system relies on a gravity feed from the fuel tanks to ensure adequate fuel flow to the engine under normal operating conditions. The electric fuel pump is used as an auxiliary component, activated primarily in specific scenarios such as engine start or when the aircraft is operating at high angles of attack or low fuel levels, where gravity feed may not be sufficient.

This design enhances safety by ensuring that the primary fuel delivery method remains mechanical and gravity-based while still providing a reliable backup through the electric pump when needed. This contrasts with some other aircraft designs where the electric fuel pump plays a more central role in the fuel delivery process, which can alter system operation during various phases of flight.