(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. (Refer to Federal Air Regulations Parts 1 and 97)

AIRCRAFT APPROACH CATEGORY DoD (USAF) - The five approach categories (A thru E) are based on 1.3 times the stall speed in the landing configuration. Operational agencies determine the category/categories of minima required and to be used by their aircraft. For example, if the final speed is 145 knots, category D minima should be used, provided other aircraft characteristics (e.g., restricted downward vision angle) do not dictate use of a higher category of minimums.
APPROACH  SPEED 
CATEGORY 
A  Speed less than 91 knots. 
B  Speed 91 knots or more but less than 121 knots. 
C  Speed 121 knots or more but less than 141 knots. 
D  Speed 141 knots or more but less than 166 knots. 
E  Speed 166 knots or more. 

NOTE: Procedures containing the word COPTER in the procedure title, i.e., COPTER VOR 190°, are approved under TERPs helicopter criteria for helicopter use only and are restricted to 90 knots or less indicated airspeed.
AIRCRAFT CLASSES (FAA-P/CG) - For the purposes of wake turbulence, separation minima, Air Traffic Control classifies aircraft as heavy, large and small as follows:
(1)
HEAVY - Aircraft capable of take-off weights of more than 255,000 pounds whether or not they are operating at this weight during a particular phase of flight.

(2)
LARGE - Aircraft of more than 41,000 pounds, maximum certificated take-off weight, up to 255,000 pounds.

(3)
SMALL - Aircraft of 41,000 pounds or less, maximum certificated take-off weight.

AIRCRAFT CLASSES (ICAO) - For the purposes of wake turbulence separation minima, Air Traffic Control classifies aircraft as heavy, medium and light as follows: