The cockpit voice recorder from the accident off Shetland in 2013, in which four people died, was recovered by the Air Accidents Investigation Branch.
Prosecutors have not been able to access vital data to examine whether anyone was criminally responsible.
The ruling will be issued at midday.
The Air Accidents Investigation Branch (AAIB) has the right to initial access to the cockpit voice recorder but it routinely chooses not to hand over the material to other bodies - in this case the Crown prosecutors.
The BBC Scotland news website revealed last year an order was being sought at the Court of Session to access the data. It is a rare legal move.
A total of 18 people were on board when the Super Puma crashed on its approach to Sumburgh.
Helicopter passengers Sarah Darnley from Elgin, Gary McCrossan, from Inverness, Duncan Munro, from Bishop Auckland, and George Allison, from Winchester, lost their lives.
A ruling into a bid by Scotland's top law officer to try to get air accident investigators to hand over the black box from a North Sea helicopter crash is to be issued.