IMO HSC code
Directional control system
5.2.1 The probability of total failure of all directional control system
should be extremely remote when the craft is operating normally, i.e.,
excluding emergency situations such as grounding, collision or a major
5.2.2 A design incorporating a power drive or an actuation system employing
powered components for normal directional control should provide a secondary
means of actuating the device unless an alternative system is provided.
5.2.4 The directional control system should be constructed so that a single
failure in one drive or system, as appropriate, will not render any other
one inoperable or unable to bring the craft to a safe situation. The Administration
may allow a short period of time to permit the connection of a secondary
control device when the design of the craft is such that such delay will
not, in their opinion, hazard the craft.