Lateral separation exists for:
NOTE: In FIG 8-4-5, the protected airspace for westbound flight A is distance “a” (50 miles), and for southwest bound flight B, distance “b” (10 miles). Therefore, the sum of distances “a” and “b”; i.e., the protected airspace of Aircrafts A and B, establishes the lateral separation minimum (60 miles) applicable for either flight relevant to the other.
NOTE: (See FIG 8-4-6.) At the first point of protected airspace overlap, the protected airspace for westbound flight A is distance “a” (50 miles), and for southbound flight B, distance “b” (40 miles). The sum of distances “a” and “b” (90 miles) establishes the lateral separation minimum applicable in this example for either flight as it approaches the intersection. For example, Aircraft B should be vertically separated from Aircraft A by the time it reaches point “p.”
NOTE: (See FIG 8-4-7.) Distance “a” (50 miles) and “b” (30 miles) are determined at the last point of protected airspace overlap. The sum of the distances “a” and “b” (80 miles) establishes the lateral separation minima applicable for either flight after it passes beyond the intersection. For example, Aircraft B could be cleared to, or through, Aircraft A’s altitude after passing point “r.”