14 C.F.R. § 29.83
(a) For each Category B rotorcraft, the horizontal distance required to land and come to a complete stop (or to a speed of approximately 3 knots for water landings) from a point 50 feet above the landing surface must be determined with—
(b) Each multiengined Category B rotorcraft that meets the powerplant installation requirements for Category A must meet the requirements of—
[Doc. No. 24802, 61 FR 21900, May 10, 1996; 61 FR 33963, July 1, 1996]