What is the main consideration for flying at "1000' on TOP" in terms of visibility?

When flying at "1000' on TOP," the primary consideration for visibility is that it must be at least 3 statute miles (SM). This requirement ensures that pilots have sufficient visual references to navigate safely and avoid potential hazards, as well as to maintain situational awareness during flight.

The concept of flying "on TOP" usually refers to an aircraft flying above cloud cover or fog, where visual reference to the ground or horizon may not be possible. In such scenarios, adequate visibility becomes crucial to maintain safe separation from other aircraft and to facilitate a safe descents or approaches when returning to lower altitudes. A visibility requirement of 3 statute miles is aligned with regulations that provide a margin of safety for pilots operating in these conditions.

Maintaining this visibility standard also helps the pilot to effectively manage the flight, detect nearby aircraft, and respond to any unforeseen circumstances that may arise during the flight.