While paradoxically rarely mentioned in legislation, helicopters represent the preferred and safest method of platform preferred and safest method of platform evacuation, provided they are available in the North Sea, both commercial and official helicopters are used, and they would only be ineffective due to weather on less than 3% of occasions. The evacuation of 6 typical North Sea platforms was simulated by computer, and platforms was simulated by computer, and in the worst cases the platforms saw offshore based machines in action within one hour, joined by shore based helicopters in the second hour, with evacuation complete inside 3 hours. Recent precautionary evacuations where helicopters were used support the simulation results. These methods can be used by platform operators in evaluating evacuation as part of formal safety assessments.
It is well established that, save where there is a gangway to another platform, the method of platform evacuation generally preferred in the North Sea is by helicopter. However, except for purely precautionary evacuations, the platform precautionary evacuations, the platform occupants would normally be mustered and prepared for lifeboat evacuation (in case prepared for lifeboat evacuation (in case conditions suddenly became worse), but would be called forward for helicopter boarding as soon as helicopter capacity became available.
Even if a helicopter were by chance or design already on the helideck at the moment of the decision to evacuate, it could not normally lift all the platform occupants at once.