Aircraft approach category means a grouping of aircraft based on a Vref (reference landing speed), if specified, or if Vref is not specified, 1.3 Vso (stalling speed or minimum steady flight speed in the landing configuration), both at the maximum certificated landing weight. Vref, Vso, and the maximum certificated landing weight are those values as established by the certification authority. In 2002, 14 CFR 97.3 was changed to include Vref as well as 1.3 Vso to establish approach category.
An aircraft’s approach category does not change if the actual landing weight is less than the maximum certificated landing weight. The certificated approach category is permanent and independent of the changing conditions of day-to-day operations. An aircraft is certificated in only one approach category and cannot be flown to the minimums of a slower approach category, e.g., a category C aircraft cannot utilize category B minimums.
Pilots are responsible for determining if a higher approach category applies
If the requirement for a faster approach speed places the aircraft in a higher speed approach category, the minimums for the appropriate higher category must be used, e.g., emergency returns requiring overweight landing, approaches made with inoperative flaps or in icing conditions, e.g., category C aircraft may be required to apply category D minimums.
The Approach categories are as follows:
(1) Category A: Speed less than 91 knots.
(2) Category B: Speed 91 knots or more but less than 121 knots.
(3) Category C: Speed 121 knots or more but less than 141 knots.
(4) Category D: Speed 141 knots or more but less than 166 knots.
(5) Category E: Speed 166 knots or more
This definition and explanation of Aircraft Approach Category was published in a 2012 FAA SAFO