What is the visibility requirement for takeoff in aircraft with two or more engines under Parts 121, 125, 129, and 135?

The visibility requirement for takeoff in aircraft with two or more engines under Parts 121, 125, 129, and 135 is primarily set at 1 mile. This standard reflects the regulatory framework that prioritizes safety while considering operational capabilities of multi-engine aircraft in various weather conditions. For these aircraft, a visibility of 1 mile is deemed adequate to execute a safe takeoff, ensuring that pilots have enough visual reference to assess the runway and surrounding environment while adhering to the operational limitations dictated by their respective regulations.

Having visibility lower than this threshold, such as 0.5 mile, would not meet established safety standards for multi-engine operations, which require clearer conditions to account for the added complexity in handling, navigation, and potential go-around scenarios that may arise during takeoff. Therefore, the correct standard for visibility in this context is 1 mile, ensuring pilots can safely complete the takeoff phase under appropriate weather conditions.