When can you start your turn onto the 15 DME arc while proceeding toward the station on the 350° radial at 300 KTAS?

In the context of navigation procedures using DME (Distance Measuring Equipment), the ability to commence a turn onto a DME arc is dictated by specific criteria regarding when the aircraft will be within the necessary distance to intercept the arc accurately while maintaining the required distance from the station and avoiding airspace conflicts.

When approaching the 15 DME arc while on the 350° radial, it is critical to ensure that the turn is initiated at a distance that allows for a smooth transition onto the arc at the correct distance. The correct distance to start the turn onto the 15 DME arc is identified as 18 NM. Initiating the turn at this distance ensures that the aircraft arrives at the arc at the appropriate point while also allowing for enough time to configure and stabilize the turn.

Starting the turn too early or too late can cause difficulties in maintaining the correct 15 NM arc, possibly leading to an overshoot or undershoot of the intended arc distance. Thus, beginning the turn at 18 NM provides pilots enough room to manage their aircraft speed, bank angle, and to ensure compliance with ATC requirements while adhering to safe navigation practices. This distance also aligns with standard operating procedures for DME arc interceptions that account for the aircraft's speed and performance characteristics