What is the lowest visibility requirement for takeoff under part 91?

The lowest visibility requirement for takeoff under Part 91 of the Federal Aviation Regulations is indeed no restrictions, which means that a pilot is not mandated to adhere to a specific minimum visibility requirement as long as they are operating under visual flight rules (VFR) conditions. This allows pilots to make decisions based on their own assessment of visibility and other conditions relevant to safe operations.

Under Part 91, pilots have the discretion to determine the adequacy of visibility and are often required to ensure that they can see and avoid other aircraft and obstacles. Thus, as long as the pilot operates within the legal framework and the aircraft is equipped to fly safely based on current conditions, there are technically no minimum visibility requirements imposed.

This flexibility is significant for pilots operating under VFR, where they are expected to navigate and make judgments based on their own visual assessment, rather than strict regulatory thresholds.