How should the FMS position be treated before use in navigation?

The Federal Aviation Administration (FAA) and general aviation best practices emphasize the importance of verifying navigational aids before use in navigation. The Flight Management System (FMS) may provide a position based on various inputs from sensors and systems; however, these inputs can be subject to error due to sensor drift, improper initialization, or other malfunctions. Therefore, it is crucial to check the FMS position for accuracy before relying on it for navigation.

This verification process often involves cross-referencing the FMS position with other navigational aids or systems, such as GPS, VORs, or visual reference points. Ensuring the accuracy of the FMS helps prevent navigational errors that could lead to deviations from the intended flight path or even safety hazards.

While it might be tempting to assume the FMS position is correct, doing so without verification compromises safety. Opining that good weather conditions allow the use of unverified systems ignores the inherent risks associated with navigational reliance on potentially inaccurate data. Similarly, while checking the compass can provide additional situational awareness regarding heading, it does not replace the need to validate the accuracy of the FMS position. Therefore, the appropriate procedure is to always check the FMS position for accuracy before use in navigation.