2.5.1 The Administration should be satisfied that
when operating in the non-displacement and transient modes within
approved operational limitations, the craft will, after a disturbance
causing roll, pitch, heave or any combination thereof, return to the
original attitude.
2.5.2 The roll and pitch stability of each craft
in the non-displacement mode, should be determined experimentally
prior to entering commercial service and be recorded.
2.5.3 Where craft are fitted with surface piercing
structure or appendages, precautions should be taken against dangerous
attitudes or inclinations and loss of stability subsequent to a collision
with a submerged or floating object.
2.5.4 The Administration should be satisfied that
the structures and components provided to sustain operation in the
non-displacement mode should, in the event of agreed damage or failure,
provide adequate residual stability in order that the craft may continue
safe operation to the nearest place where the passengers and crew
could be placed in safety, provided caution is exercised in handling.
2.5.5 In designs where periodic use of cushion
deformation is employed as a means of assisting craft control, or
periodic use of cushion air exhausting to atmosphere for purposes
of craft manoeuvring, the effects upon cushion-borne stability should
be determined, and the limitations on the use by virtue of craft speed
or attitude should be established.