Which phase of flight is associated with the highest GPS accuracy of 0.3 nm?

The phase of flight associated with the highest GPS accuracy of 0.3 nautical miles is the final approach. During the final approach phase, aircraft are typically aligned and stabilized on the glide slope for landing, which requires highly accurate position information for both operational safety and efficiency. GPS accuracy is critically important in this phase to ensure that the aircraft is correctly descending towards the runway and to provide precise guidance to pilots.

Final approaches often utilize advanced navigation technologies and procedures that leverage the highest level of GPS performance, allowing pilots to accurately navigate to runway thresholds. This level of accuracy is vital for maintaining the required safety margins in altitude and lateral positioning when aircraft are close to the ground.

In comparison, during the enroute and terminal phases of flight, while GPS can also provide reliable navigation information, the accuracy specifications are not as stringent, often allowing for a higher potential deviation. The departure phase, while important, focuses more on climbing out and establishing route clearance, and does not necessitate the extreme precision required in the final approach phase.