FlyByWire has released an update for the A32NX, introducing secondary flight plan functionality within the Airbus MCDU’s Flight Management System. The feature allows pilots to pre-plan an alternate routing that runs in parallel with the active flight plan, supporting realistic handling of abnormal, contingency, and time-critical scenarios in Microsoft Flight Simulator.
Secondary Flight Plan Capability in the A32NX
The secondary flight plan exists independently from the active flight plan and can be fully prepared in advance. It supports standard lateral flight planning functionality, including route construction and SimBrief route uplink, while remaining isolated from active flight guidance until explicitly activated.
On the flight deck, the secondary flight plan is visually distinguished from the active route, allowing crews to review and verify alternate routing without affecting the primary plan. This separation enables crews to prepare contingency options during low-workload phases of flight. At present, performance and fuel predictions are not computed for the secondary flight plan. FlyByWire has confirmed that predictive calculations are planned for a future update.
Operational Use Case: Engine Out Departure Planning
In real-world Airbus operations, one of the most common uses of a secondary flight plan is preparation for an engine failure during takeoff. This is especially relevant at airports with surrounding terrain where standard instrument departures may not be suitable following a loss of thrust.
In an example outlined by FlyByWire, a flight departing Zurich for Munich is planned using Runway 28 with a standard SID in the primary flight plan. Due to terrain constraints near the airport, the published SID cannot be safely followed in an engine-out scenario. Instead, an alternate routing is pre-planned that initially follows runway heading, transitions onto a defined VOR radial, and leads into a holding area where the crew can stabilize the situation and assess next steps.
This routing is fully prepared in the secondary flight plan before departure, allowing immediate activation if required without additional flight plan modification during a high-workload phase.
Integrated Return and Approach Preparation
The secondary flight plan can also include preparation for a return to the departure airport. In the Zurich example, the alternate routing includes a planned return approach following the holding phase, enabling a structured transition back to the airport.
Approach performance data can be entered for the secondary flight plan in advance. This allows crews to transition directly into approach preparation after activation, reflecting real-world Airbus procedures where abnormal scenarios are anticipated before departure.
Activation Logic and Plan Management
Activation of the secondary flight plan follows Airbus-specific logic. The option to activate or swap plans is only available when the aircraft is in heading mode or when both plans share the same active leg. Once activated, all lateral and performance data from the secondary flight plan replaces the active flight plan. If retaining the original plan is necessary, the system allows crews to swap between the active and secondary plans rather than permanently overwriting the primary route.
Platform Availability and Future Expansion
Secondary flight plan functionality is now available on the FlyByWire A32NX. This addition brings the A32NX closer to real-world Airbus operational workflows, particularly in areas related to engine-out procedures, terrain-constrained departures, and rapid diversion planning.
It is not yet implemented on the A380X, though FlyByWire has indicated that support is planned for a future update. The A380X implementation is expected to expand on the concept, potentially supporting multiple secondary flight plans. FlyByWire has published detailed documentation covering example use cases and operational considerations for users seeking further technical depth.
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