The families of four victims of a fatal helicopter crash have been told a date has still not been set for a Fatal Accident Inquiry.

Nearly five years on from the tragedy, relatives of the four oil workers who died in August 2013 met with representatives of the Crown Office.

Eighteen people were aboard the Super Puma chopper when it plunged into the North Sea near Shetland in August 2013.

Duncan Munro, 46, from Bishop Auckland; Sarah Darnley, 45, from Elgin; 59-year-old Gary McCrossan, from Inverness and George Allison, 57, from Winchester died following the incident.

Ms Darnley is believed to be the first woman killed in a North Sea oil industry helicopter crash.

Earlier this year her mother told STV news of her frustration.

"Well it wouldn't make any difference to us because they're not coming back, but it would just finish it," she said.

"And that's what we want - for it to be finished with and get on."

Air accident investigators found that decreasing airspeed had gone unnoticed by pilots before the crash

The Crown Office says the ongoing investigation is complex and challenging and it will continue to keep the families informed of all significant developments.

A spokesman for the Crown Office said: "The investigation into the Sumburgh helicopter crash on 23 August 2013 by Police Scotland, working with the assistance of the Civil Aviation Authority and under the direction of the Crown is ongoing.

"The Air Accidents Investigation Branch report covering the safety investigation was published in March 2016 and raised a number of issues that require to be considered as part of the wider investigation.

"We will endeavour to carry out our investigation as quickly as possible but the investigation is highly complex and challenging and requires specialist input from those with the necessary expertise in civil aviation.

"We will continue to keep the families advised of all significant developments."