Final answer:
A 'FD DADC DATA INVLD' message on the FMA indicates an error or invalid data in the aircraft's DADC system. Troubleshooting and diagnosing the specific cause of the invalid data is necessary to resolve the issue.
Step-by-step explanation:
A 'FD DADC DATA INVLD' message on the FMA (Fault Management Application) usually indicates an error or invalid data in the DADC (Digital Air Data Computer) system. The DADC is responsible for providing accurate flight-related data, such as airspeed, altitude, and vertical speed, to the aircraft's systems.
This message could mean that there is a problem with the DADC's sensors, signal processing, or data communication. It could also indicate a fault in the system that processes and interprets the data from the DADC.
In order to resolve this issue, it would be important to troubleshoot and diagnose the specific cause of the invalid data, which may involve checking the sensors, wiring, connectors, and the software used to process the data.