Section 23.2310 - Buoyancy for seaplanes and amphibiansAirplanes intended for operations on water, must-
(a) Provide buoyancy of 80 percent in excess of the buoyancy required to support the maximum weight of the airplane in fresh water; and(b) Have sufficient margin so the airplane will stay afloat at rest in calm water without capsizing in case of a likely float or hull flooding.