In cobnntrext of RIDDOR as of now, it depends upon what you mean by "aircraft incident offshore" i.e was the arcraft actually involved in a crash or similar or did the employee simply have an incident in the aircraft? Refer to para 101 of L 73 i.e Avoiding dual reporting Except in the case of offshore workplaces (where HSE needs immediate information about incidents involving offshore installations or pipelines and shipping or aircraft) regulations 3, 4 and 5 do not apply to any of the events reportable under the Acts and Statutory Instruments listed in Schedule 7. This means that RIDDOR does not apply to: a death or injury associated with the operation of a civil aircraft between the (a) time anyone boards it intending to fly and the time everyone gets off; the death or injury of anyone employed on, or carried in, a merchant ship (b) (unless that person is a shore-based worker involved in loading, unloading, repair work etc); any incident involving the escape from control of a radioactive substance; and(c) any dangerous occurrence on board a merchant ship.