Helicopter operators reacted quickly yesterday, after Sikorsky released an Alert Service Bulletin requiring 11 hours of maintenance prior to their next flight. Despite the odds, operators Bristow and Babcock were able to ensure that a significant portion of their aircraft were able to fly today, just to find operations hampered by high sea states and triggered lightning.

Some areas of the North Sea today will encounter Sea State 7 which indicates wave heights from 20 to 30 feet. No North Sea helicopter is permitted to operate in areas with waves of such height.

Wave height at first thought would appear unrelated to aviation and something that one would not normally consider when flying helicopters thousands of feet above the sea. However helicopter operators have to operate on a worst case scenario and factor in the fact that should a technical issue occur, the aircraft may have to ditch in the sea. All helicopters have certified sea state ditching limits and no North Sea helicopter is certified past Sea State 6.

Operations are also being affected by a phenomenon called triggered lightning, a situation that is extremely dangerous for helicopters and results in flights through high risk areas being suspended. The explanation for triggered lightning is that the aircraft acquires a negative electrical charge during flight and when the helicopter passes through certain positively charged cloud formations, it can result in a triggered lightning strike on the airframe – a situation that can cause devastating consequences for helicopter safety. Oil and gas people have previously written an informative article on triggered lightning.

With not one helicopter flying above the UK sector of the North Sea as of 10:20am this morning, it is expected that only a fraction of North Sea flights will be able to reach their destination, in a move that will cause further dismay to stranded offshore workers.