A meeting of the Helicopter Safety Steering Group, made up of representatives of operators, oil companies and unions, was held in Aberdeen but the cause of the ditching was not discussed.
RMT offshore organiser Jake Molloy said: "The operator CHC and the others are unable to provide any information about the causes of the ditching because they are bound by the protocols of AAIB, which dictate you cannot discuss findings until their investigation has concluded.
"So we await that to be wound up, which could be done by tonight or in the next few days.
"It's frustrating and disappointing for workers as it means we are not in a position to discuss the way forward. Many of the workforce will be extremely frustrated as some will be stuck offshore or alternatively stuck onshore, some of them perhaps not being paid."
The helicopter was carrying an oil crew from Aberdeen to a rig 86 miles north west of Shetland when it ditched at around 3.30pm on Monday. The 17 passengers and two crew were taken off their life raft by a rescue boat launched from the Nord Nightingale tanker which was close to the scene.