If both primary flight displays fail, what is the recommended backup source and procedure?

• A. Use standby instruments for attitude, heading, altitude and airspeed; follow ECAM and QRH for fault isolation; maintain control with crew coordination.
• B. Continue using the GPS heading and altitude as primary sources only.
• C. Maintain flight using only engine instruments and autopilot for stability.
• D. Shut down the aircraft and return for an immediate landing.

Answer: (C)

When both primary flight displays fail, the aircraft must be kept controllable using a reliable, non-visual reference and a stable flight mode. The engine instruments remain available and give continuous, objective data about thrust, fuel flow, and engine performance. By trusting these indicators, you can manage airspeed, engine power, and energy state to keep the airplane in a safe flight envelope. Engaging the autopilot allows the airplane to maintain a steady attitude and altitude with less pilot workload while you follow the QRH to isolate the fault and attempt to restore the PFDs.

So, the recommended backup is to rely on the engine indications for performance awareness and to use the autopilot to maintain stable flight, while you troubleshoot and carry out the prescribed procedures. This approach avoids depending on degraded or unavailable primary display information and provides a safer, lower-workload means to keep the aircraft under control during restoration.