Definition
Two or more aircraft on courses whose tracks differ by less than 45 degrees, including aircraft following the same track or routing in the same general direction along an airway, route, or course.
Plain English
Aircraft that are heading in close to the same direction — within 45 degrees of each other's path — so they are essentially going the same way.
Context Anchor
You will see this term in air traffic control and separation discussions, especially when describing how controllers judge the relationship between two aircraft paths.
Why Pilots Care
Determines the specific time or distance interval a controller must maintain between the aircraft.
Intuition Check
Same direction does not mean exactly the same heading. Here it means generally moving the same way, with less than a 45-degree angle between the aircraft paths.
Example Sentence 1
ATC reported same direction traffic at our twelve o'clock, ten miles ahead, two thousand feet below.
Example Sentence 2
Same direction aircraft on converging routes still require the longer longitudinal separation standard.