Text in force at 23-63: from 23-45, effective 7 Sep 1993.
(a) Each main float must have--
[(1) A buoyancy of 80 percent in excess of the buoyancy required by that float to support its portion of the maximum weight of the seaplane or amphibian in fresh water; and
(2) Enough watertight compartments to provide reasonable assurance that the seaplane or amphibian will stay afloat without capsizing if any two compartments of the main floats are flooded.]
(b) Each main float must contain at least four watertight compartments approximately equal in volume.
58 FR 42165 · Source