The Aberdeen-based company said it was continuing to be hit by a downturn in the oil and gas industry.
It said it had taken measures to cut costs but had not been able to meet levels needed and 130 employees may now be made redundant.
Pilots union Balpa has called for a summit to be held urgently on jobs security and said it would be fighting to save the threatened posts.
Consultation between Bristow and unions will now get under way.
North Sea helicopter operator Bristow could make 130 of its staff redundant.