For the purposes of this part, an ultralight vehicle is a vehicle that

(a) Is used or intended to be used for manned operation in the air by a single occupant;

(b) Is used or intended to be used for recreation or sport purposes only;

(c) Does not have any U.S. or foreign airworthiness certificate;

and (d) If unpowered, weighs less than 155 pounds ( 57 Kgs ) ;

or (e) If powered (1) Weighs less than 254 pounds ( 94 Kgs ) empty weight, excluding floats and safety devices which are intended for deployment in a potentially catastrophic situation; (2) Has a fuel capacity not exceeding 5 U.S. gallons ( 19 Liters ) ; (3) Is not capable of more than 55 knots ( 101 Km/h ) calibrated airspeed at full power in level flight; and (4) Has a power-off stall speed which does not exceed 24 knots ( 44 Km/h ) calibrated airspeed.