Visual Separation

A means employed by ATC to separate aircraft in terminal areas and en route airspace in the NAS. There are two ways to effect this separation:
  1. The tower controller sees the aircraft involved and issues instructions, as necessary, to ensure that the aircraft avoid each other.
  2. A pilot sees the other aircraft involved and upon instructions from the controller provides his/her own separation by maneuvering his/her aircraft asnecessary to avoid it. This may involve following another aircraft or keeping it in sight until it is no longer a factor.

Source: Pilot Contoller Glossary (PCG)

See also: