sentences:  Bristow intends to order more than 10 tiltrotors.Bristow helicopters operated Sikorsky S-61N helicopters on behalf of Her Majesty's Coastguard, the United Kingdom's Coast Guard, until July 2007 after which there was a 12-month transitional period whilst CHC Helicopter took over the contract replacing the S-61N with new helicopters.Bristow operated four dedicated Search and Rescue (SAR) sites in the UK, on behalf of HM Coastguard.