Definition
A grouping of aircraft based on a reference landing speed (VREF), or if VREF is not specified, 1.3 times the stall speed in landing configuration (VSO) at the maximum certificated landing weight. The five categories are: Category A (speed less than 91 knots), Category B (91 knots or more but less than 121 knots), Category C (121 knots or more but less than 141 knots), Category D (141 knots or more but less than 166 knots), and Category E (166 knots or more). An aircraft must use the minimums for its category, or for any higher category if a faster approach speed is flown.
Plain English
Aircraft are sorted into speed groups (A through E) based on how fast they fly the final approach to landing. Each group has its own published minimum altitude and visibility requirements on instrument approach charts, because faster aircraft need more room to maneuver and stop.
Context Anchor
Seen on instrument approach charts and in landing minimums, especially when choosing the correct minimum descent altitude, decision altitude, visibility, or circling minimums for the aircraft.
Why Pilots Care
The category sets the minimum visibility and decision altitude or height required to continue the approach.
Intuition Check
Do not assume aircraft approach categories are based on aircraft size, weight, or engine type. In this FAA use, they are based on approach speed.
Example Sentence 1
Our VREF on this approach is 135 knots, so we use the Category C minimums on the approach plate.
Example Sentence 2
When operating a faster airplane in category C, the pilot must meet higher visibility requirements on the same approach.