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.

The number of jobs created was well above analysts' forecasts of about 225,000 new jobs in the month.
US employers have added at least 200,000 jobs for 10 months in a row, the longest period of jobs growth since 1995.
The number of jobs created has averaged 241,000 a month this year.
The Labor Department added that 44,000 more jobs were created in September and October combined than the government had previously estimated.
But as in the UK, stronger job creation has yet to lead to a significant increase in salaries.
Analysts said the US economy would continue to improve, despite lower global growth expectations.
They added that companies hiring temporary workers for the winter holidays could be providing a boost to the overall jobs figure,
The US economy is less dependent on exports than Germany, China and Japan, but is more reliant on domestic consumer spending.
Delivery firms have announced ambitious recruitment plans. UPS has said it expects to add up to 95,000 seasonal workers, up from 85,000 last year. FedEx plans to hire 50,000, up from 40,000.
The National Retail Federation estimates that seasonal retail hiring could grow by about 4% to as much as 800,000.
Most recent figures suggest Americans are buying more cars, which is likely to keep factories busy in coming months. Auto sales last month rose to their second-fastest pace this year. Car sales are on track to rise 6% this year from 2013.
The economy is expected to slow in the final three months of the year to an annualised growth rate of 2.5%, down from 4.3% from April to September.
Meanwhile, the US trade deficit fell slightly in October, as exports rebounded, while oil imports dipped to the lowest level in five years.
The deficit edged down 0.4% to $43.4bn, as against a revised $43.6bn in September, the Commerce Department reported.
Exports climbed 1.2% to $197.5bn, recovering after a September dip.
Imports also rose by 0.9% to $241bn, but that increase was tempered by a 0.6% fall in imports of petroleum, which dropped to the lowest level since November 2009.
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.
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The US economy added 321,000 jobs in November, while the unemployment rate stayed at 5.8%, official Labor Department figures show.