Aviation watchdogs were forced to bring forward the lifting of the Super Puma flight ban due to fears over a media leak.
The UK and Norwegian Civil Aviation Authorities announced the lifting of the grounding late on Friday, in a move which caught industry offguard.
Unions expressed their frustration on hearing that the ban was being lifted suddenly after month of talks about the aircraft returning to service.
But it has now emerged that the scheduled lifting of restrictions was to be announced this week.
Only rumours of a leak on the Norwegian side of operations led to the statement being issued at 8pm on Friday night.
A spokesman for the UK CAA said: “There was talk of a leak in Norway.
“They felt they couldn’t wait any longer.”
He added: “In everything we’ve said up to now we’ve made it clear that this has not been a decision we have taken lightly.
“We know the feeling of apprehension, that’s why these restrictions were in place.”
The CAA could not provide a timeline for when the Super Pumas may return as it is up to individual helicopter operators to make the decision and come forward with a safety case.
The spokesman added: “It’s certainly not something that could in days.”