Helicopter Surveillance System Boosts North Sea Offshore Flight Safety

Oil & Gas UK and NATS Services Ltd have launched a new helicopter surveillance system for the North Sea, the first in the world for offshore operations. The new system enables air traffic controllers to see helicopters on their radar screens at Aberdeen Airport at a far greater range from the shore than has previously been possible using solely shore-based radars. Using this new system will further reduce the risk of near miss incidents with other aircraft and increase the speed and efficiency of search and rescue operations.

Commenting on behalf of the Helicopter Task Group, which was instrumental in pushing forward the project, Bob Keiller, chair of the group said, "This new system, a key work area of the task group, is a breakthrough in helicopter safety, and it is encouraging to see it going live. Previously, helicopters were lost to land-based radar at about 80 miles from the coast, because radar coverage doesn't extend beyond that distance. The new system uses multilateration to allow flight paths to be tracked all the way to an installation in real time. It is designed to detect aircraft down to 500ft above sea level or better, depending on the helicopter position."

Multilateration uses multiple position points to determine the exact location of a helicopter. To provide maximum coverage, equipment is being fitted to 16 host platforms, which have been divided into four clusters each of four platforms. As soon as a helicopter leaves the 80 mile radar zone, its transponder responds to a signal which is then detected by receivers on each of the four platforms in a cluster, allowing complete surveillance of the helicopter flight. This data is then sent to the control tower building (CTB) at Aberdeen Airport via the oil company data links. Computer analysis at the CTB determines the helicopter position by triangulation. Only three signals need to be received in order to provide a position, but the fourth signal both increases accuracy and gives some redundancy should a signal not be received.

Three of the four clusters are now completed and flight trials have commenced to ensure the coverage is complete from these three clusters and that the system accuracy is within the expected limits. Phase two of the flight trials is due to commence in January 2010, with all four clusters expected to be fully operational by June 2010.

Iain Harris, head of engineering for NATS Services, said, "Listening to our customers to understand their needs always comes first. Oil & Gas UK was clear that safety was paramount, and we are delighted to deliver this significant safety enhancement to the North Sea helicopter air traffic control operation. It has been a challenging project to manage due to the complexities of installing equipment offshore and the sheer number of stakeholders that were involved in delivering the surveillance and voice communications improvements for the 25,000 square miles of airspace over the North Sea.

"We are proud that we met Oil & Gas UK's needs efficiently and on budget despite these evolving challenges."

Robert Paterson, health, safety and employment issues director with Oil & Gas UK, added, "In addition to this new visual tracking system, the industry has recently upgraded VHF voice communication with offshore helicopters by modernizing and extending existing offshore rebroadcasting facilities. Rebroadcasting facilities enable the controllers to speak directly with helicopter crews through the use of offshore radios linked to shore. The new extension and upgrades ensure that the whole of the North Sea is now covered by voice communication. Improving radar and radio coverage for helicopter flights is a big step forward."