What effect does losing RAIM have on navigation?

Losing RAIM, or Receiver Autonomous Integrity Monitoring, creates uncertainty in GPS accuracy because RAIM is designed to check the integrity of the GPS signals a receiver is using for navigation. When RAIM is operational, it continuously verifies that the signals from the satellites are accurate and reliable. If RAIM is lost, the receiver can no longer guarantee the integrity of the positioning information it provides. This uncertainty can lead to a lack of trust in the accuracy of the navigation data, potentially resulting in poor navigation decisions or the inability to determine an accurate position.

The other choices do not accurately reflect the implications of losing RAIM. For instance, losing RAIM does not improve navigation accuracy, nor does it ensure that visual flight rules are adhered to. Additionally, while it might seem like reliance on Visual Flight Rules (VFR) navigation could increase, this option does not directly correlate with the primary impact of losing RAIM, which centers on the uncertainty it introduces to GPS navigation. Thus, the correct understanding is that the primary impact of losing RAIM is the uncertainty introduced in GPS accuracy.