In non-radar parallel runway operations, what minimum centerline separation and divergence angle are required to authorize simultaneous departures?

• A. 4,000 ft or more; 60 degrees
• B. 1,500 ft; 15 degrees
• C. 2,000 ft or more; 30 degrees
• D. 3,500 ft or more; 45 degrees

Answer: (D)

In non-radar parallel runway operations, you rely on published separation criteria rather than air traffic radar vectors. The goal is to ensure two departing aircraft on parallel runways won’t come into conflict as they climb, so you must have enough lateral separation plus a rapid enough divergence of their flight paths.

The minimum that meets that safety standard is 3,500 feet of centerline separation with a 45-degree divergence. The 3,500-foot spacing provides a solid horizontal gap between the two departure tracks right at takeoff, taking into account wingspans, engine blast, and wake turbulence. The 45-degree divergence means each airplane begins turning away from the other runway early in the climb, so their trajectories separate quickly and stay apart as they gain altitude.

Smaller centerline separations or smaller divergence angles don’t give enough margin for safe independent paths, which is why options with 1,500 feet and 15 degrees or 2,000 feet and 30 degrees aren’t sufficient. Larger figures, like 4,000 feet with a 60-degree divergence, would be more than the minimum required, but the question asks for the minimum combination.