Definition
Authorized takeoff visibility values that are less than the standard takeoff minimums published in 14 CFR Part 91, available only to certain commercial operators (such as Part 121, 125, and 135 operators) who hold specific operations specifications permitting their use, and who meet the associated equipment, crew qualification, and runway requirements.
Plain English
Permission for some commercial operators to take off in worse visibility than the normal rules allow, granted because the operator, the crew, and the runway all meet extra requirements.
Context Anchor
Seen in instrument procedure publications and operations guidance when checking whether a commercial flight may legally depart in low-visibility conditions.
Derivation
Minimum comes from a Latin word meaning “smallest.” In aviation, minimums are the lowest allowed values for something, such as visibility, not suggested targets or comfort levels.
Why Pilots Care
Determines whether a commercial flight can legally depart in marginal visibility; unauthorized use can result in enforcement action or loss of operating privileges.
Grounding Statement
If the visibility is below the normal takeoff limit, lower-than-standard minimums tell an authorized crew whether departure is still allowed.
Intuition Check
Do not read “lower-than-standard” as “easier” or “less strict.” It means the required visibility number is lower, but the permission to use it is more controlled and must be specifically authorized.
Example Sentence 1
Because the airline held authorization for lower-than-standard minimums, the captain was able to depart with reported visibility below what a private pilot would be allowed to use.
Example Sentence 2
With the enhanced vision system installed and the proper training completed, the operator was approved for lower-than-standard minimums at the departure airport.