A UNION has demanded urgency in improving safety on Super Pumas, as some workers complained they were being forced back into the helicopters after last month's crash killed four people.

Unite spoke out after Finance Secretary John Swinney said the correct approach was to wait for the findings of the Air Accidents Investigation Branch (AAIB) before deciding if a public inquiry is necessary into the tragic crash.

There is concern that Super Pumas have been cleared to fly again after a voluntary suspension, despite the fact the AAIB said it is too early to say whether they were safe to fly.

At least one helicopter firm began passenger flights to oil and gas installations after the crash off Shetland involving an AS332 L2 Super Puma on August 23.

The safety regulator, the Civil Aviation Authority, said that so far they do believe the accident was caused by an airworthiness or technical problem.

Offshore worker Will Sandison said he faced losing his job if he refused to fly in the "death traps."

He added: "I am disgusted with the decision by these companies to put any variation of Super Puma back in service.

"When you are crammed into the back of these with 17 of your colleagues with little chance of escape you desperately seek assurance that you are flying in something fit for purpose , can they say that these helicopters truly are?

"Lord Cullen's report into Piper Alpha changed the safety culture in the North Sea and has saved thousands of lives, we demand the same. We deserve no less."

Mr Swinney said: "There has to be an investigation of this particular incident, properly and fully, by the Air Accidents Investigation Branch and that has to report.

"And, as a consequence of that, it is incumbent - because this is what the law says - that the Civil Aviation Authority has to consider and apply any relevant changes to the safety regime as a consequence of the investigation carried out by the AAIB.

"The Government maintains the correct approach is to wait for the sequence of investigations to be undertaken before we come to any conclusion about the need for a wider inquiry."

Because many of the issues raised by such an inquiry are reserved to Westminster, the UK Government would also need to agree to this, Mr Swinney said.

Unite Scottish Secretary Pat Rafferty said the Scottish Government should not be waiting on the final report by the AAIB to begin the process of reforming offshore health and safety and basic questions about the conditions facing workers on helicopter transfers needed answering.

Mr Rafferty said: "It is not just a question of whether the Super Puma fleet is airworthy; it's also a question of whether they are fit for the purpose of commercial transfer."

Labour MSP Iain Gray said the helicopter transport system for North Sea oil workers will only be restored by a full, independent public inquiry.