Determine the number of aircraft to acquire proper interval. What condition indicates you have interval?

The condition that indicates you have proper interval in the T-6B Primary Flight Training context is when the aircraft ahead of you is abeam or behind your wingtip and has completed at least 90° of turn. This specific positioning ensures that you have adequate spacing and can safely manage your approach to landing.

When another aircraft is abeam your wingtip, it is in a position that allows you to maintain a safe distance, as they are not directly in front of you, thereby reducing the risk of wake turbulence or mid-air conflict. Additionally, the requirement that the aircraft has completed at least 90° of turn confirms that they are moving away from the traffic pattern you are about to enter. This positioning is crucial for ensuring that each aircraft can operate without interference, allowing for a safe and efficient landing sequence.