UNIONS have called for a full inquiry into last month's helicopter crash in the North Sea, saying they are "appalled" a fatal accident inquiry into the deaths of 16 people killed in a crash off Aberdeenshire in 2009 has still not been launched.

After expressing sympathy to relatives of those killed and injured in the tragedy off Shetland on August 23 - the fifth incident involving Super Puma helicopters in the past four years - a conference pressed oil firms to increase investment in new helicopters that ferry workers to and from rigs.

An emergency motion at conference was unanimously approved, which included support for workers who refuse to travel on Super Puma helicopters until all health and safety concerns have been answered.

Delegates insisted that inquiries should be held into the causes of a number of incidents in recent years.

David Hulse, of the GMB union, said workers had "genuine concerns" about the safety of flights.

Super Puma flights have now resumed but Mr Hulse said he believed they should have remained grounded until all safety concerns had been properly dealt with.

Mark Lyon, of Unite, said August 23 was a "terrible day" for the offshore industry because of the crash, in which four people died.

"We want a public inquiry, similar to the inquiry into the Piper Alpha tragedy 25 years ago," he said.

Unions also called for more safety representatives, carrying out regular risk assessments.

l The funeral of Sarah Darnley, 45, of Elgin, who was killed in last month's crash, has taken place at Moray Crematorium.