When does VOR and VOR/DME station passage occur?

VOR and VOR/DME station passage occurs when the TO-FROM indicator makes the first positive change to FROM. This is a key point in navigation as it indicates that the aircraft has crossed the radial associated with the VOR station. Prior to this point, the aircraft is on the course leading to the VOR, and once the indicator changes to FROM, it signifies that the aircraft is now on a course away from the station.

Understanding this concept is essential for pilots who rely on VOR navigation, as it allows them to accurately determine their position relative to the VOR station and make necessary course adjustments. Monitoring the TO-FROM indicator is an integral part of using VOR systems effectively during flight, ensuring that pilots are aware of their proximity to the station and enabling them to navigate safely. The other options do not accurately represent the moment of station passage, as they either focus on range stability or the maximum deviation from the course, which do not specifically indicate the point of crossing the station's radial.