In a nonradar environment, when the takeoff direction differs by at least 45° from the reciprocal of the final approach course, the departure must take off before the arrival leaves a fix inbound not less than ___ mile(s) from the airport.

• A. 2 miles
• B. 4 miles
• C. 6 miles
• D. 8 miles

Answer: (B)

In nonradar environments, separation between departing and arriving aircraft is achieved through published distance and positioning rules rather than radar vectors. When the takeoff direction differs by at least 45 degrees from the reverse of the final approach course, there’s a need for a fixed buffer so the inbound aircraft won’t come too close to the departing path as both aircraft maneuver.

The required buffer distance is four miles from the airport. This distance gives enough time and space for the inbound aircraft to continue toward the approach path while the departure climbs away, reducing the risk of conflict as their tracks cross or run parallel after one leaves the vicinity of the field.

If you see other distances offered, they don’t fit the standard. A shorter distance would erode the safety buffer, while a longer distance would unnecessarily constrain operations in nonradar airspace. Four miles is the established minimum to maintain safe separation under these conditions.