What does the BRAKE ACCU CAS message signify?

The BRAKE ACCU CAS message is an indication that the pressure in the brake accumulator has fallen below a critical threshold, specifically 1900 PSI. In the context of the Falcon 2000LXS, the brake accumulator is a crucial component of the braking system that provides hydraulic pressure for brake applications, particularly during the initial stages of landing or when the aircraft is stationary.

When this CAS message appears, it alerts the pilot that the accumulator's pressure is insufficient for reliable brake performance. Therefore, it is essential to address this issue immediately to ensure safe operation of the aircraft, involving either confirming the status of the parking brake or performing necessary maintenance to restore adequate pressure.

The other choices do not accurately describe the significance of the BRAKE ACCU CAS message, as they either indicate conditions that are not related to accumulator pressure or do not correctly reflect the operational status of the braking system.