What is the minimum radar separation provided by Parallel ILS approaches between successive aircraft on adjacent localizer courses?

The minimum radar separation provided by Parallel ILS approaches between successive aircraft on adjacent localizer courses is indeed 1 1/2 miles. This distance is critical for ensuring that aircraft can safely land while maintaining enough separation to avoid interference with each other's navigation signals.

When aircraft are approaching on parallel localizer courses, the 1 1/2 miles separation is a standard that helps to account for potential deviations in the flight path and ensures that any slight lateral drift does not lead to a loss of separation. This standard is established to promote safety and efficiency in operations where multiple aircraft are landing simultaneously, especially in busy air traffic environments.

The specific distance of 1 1/2 miles takes into consideration various operational factors, including the speed of the aircraft and the precision of the landing systems being used. Each of the other options provided does not align with the established minimum separation required by regulations and operational standards.