AIM 5-5-12

Pilot. Acceptance of instructions to follow another aircraft or to provide visual separation from it is an acknowledgment that the pilot will maneuver the aircraft as necessary to avoid the other aircraft or to maintain in‐trail separation. Pilots are responsible to maintain visual separation until flight paths (altitudes and/or courses) diverge.

If instructed by ATC to follow another aircraft or to provide visual separation from it, promptly notify the controller if you lose sight of that aircraft, are unable to maintain continued visual contact with it, or cannot accept the responsibility for your own separation for any reason.

The pilot also accepts responsibility for wake turbulence separation under these conditions.

Controller. Applies visual separation only: Within the terminal area when a controller has both aircraft in sight or by instructing a pilot who sees the other aircraft to maintain visual separation from it.

Pilots are responsible to maintain visual separation until flight paths (altitudes and/or courses) diverge.

Within en route airspace when aircraft are on opposite courses and one pilot reports having seen the other aircraft and that the aircraft have passed each other.