Three Missing After Helicopter Crash Three people are still missing after a helicopter carrying 18 workers from an oil rig ditched in the North Sea off Shetland. The Super Puma L2 aircraft went down at 6.20pm on Friday around two miles west of Sumburgh airport as it was returning to Shetland from the Borgsten Dolphin platform. A search operation involving coastguard, police, RAF and local lifeboats was launched and 15 people were rescued from the water. One of the rescued workers is moved on a stretcher The helicopter's life rafts were found empty and some wreckage from the aircraft has started to wash up at the southern end of Sumburgh, the coastguard said. A spokeswoman said: "There were 18 people on board and 15 have been recovered, there is still an ongoing search and rescue mission for the three missing people. The people that were involved are in varying stages of injury, no one has walked away from this without a scratch. The helicopter ditched two miles from Sumburgh airport Amanda Smith, the mother of one of the workers Sam Smith, said her son had telephoned her from hospital after suffering cuts in the crash. She told Sky News: "He said it seemed to lose power and there was no time to brace, they just dropped into the sea. He was by the window so he was able to escape that way as it rolled over. He said he had come off better than a lot of people. It didn't seem real, I would say two hours later it's just beginning to sink in. Some of those rescued were able to walk unaided after the rescue The helicopter's operator CHC said it was flying for oil company Total and that the aircraft lost communication as it approached the airport on the southern tip of Shetland's main island. A spokesman said: "The aircraft was on approach to Sumburgh Airport at approximately 6.20pm when contact was lost with air traffic control. We can confirm there were 16 passengers on board, and two crew. Investigators from the Air Accidents Investigation Branch are travelling to the scene. A coastguard boat searches the North Sea Two lifeboats from Lerwick and Aith are being helped at the scene by helicopters from the coastguard, RAF Lossiemouth and two Bond rescue helicopters. A Northlink ferry carrying 201 passengers between Shetland and Orkney was also diverted to the scene to help. Police Scotland said a major incident had been declared. Sumburgh Airport was closed to allow emergency services to deal with the ongoing incident. Several helicopters have been involved in the search operation A spokesman said all those rescued had been taken to Gilbert Bain Hospital in Lerwick. Jim Nicholson, RNLI rescue co-ordinator, said the helicopter is in an "inaccessible" position and that weather in the area is not "particularly good." He said: "There was a fresh wind, not overly strong, visibility is not particularly good and it was misty in the area but I doubt if that would have had any impact on causing whatever happened to the helicopter. I believe that the helicopter is in a fairly inaccessible position at the moment near the cliffs. There's quite a lot of tide in that area so any person in the water could be carried some distance away. Last year, two helicopters ditched in the North Sea only six months apart. All passengers and crew were rescued in both incidents, which were found to be caused by gearbox problems. :: CHC has set up a helpline for concerned relatives on 01224 296 866.