PSA Airlines Canadair Regional Jet Systems (PSA-CRJ) Practice Exam

What happens during cruise flight at FL300 if there is an EDP failure with hydraulic switches in the AUTO position?

1. The B pump will automatically operate to compensate.

2. The A pump will automatically operate to compensate.

3. No pumps will operate.

4. The B pump requires flaps out of zero to operate.

The correct answer is: The B pump requires flaps out of zero to operate.

During cruise flight at FL300, an EDP (Engine Driven Pump) failure occurs, and the hydraulic switches are in the AUTO position. Under these conditions, the system is designed to provide redundancy and support hydraulic needs. The correct response indicates that the B pump requires the flaps to be out of the zero position in order to operate. This feature is a crucial aspect of the hydraulic system’s operational logic. In the case of an EDP failure, the aircraft's hydraulic system manages the pressure and flow through the remaining pumps. The requirement for the B pump to have the flaps out of zero essentially means that the system will only activate the B pump when additional hydraulic demand is placed upon it through flap deployment. This ensures that the B pump does not run unnecessarily in conditions where hydraulic demand is minimal, preserving system integrity. Understanding how hydraulic pumps interact with flight control systems is vital for pilots and maintenance personnel, as it directly impacts the aircraft's operational capabilities during flight anomalies. Proper management and awareness of the hydraulic system are essential for maintaining safety and handling characteristics of the aircraft during such failures.