Aurigny is first European operator to use satellite-based approach system
A small regional operator in Britain's Channel Islands is pioneering a space-based means to ensure safer, more accurate vertically guided aircraft approaches at small airports in Europe, where conventional precision landing systems are not always economically feasible.
The first commercial operator to use the European Geostationary Navigation Overlay Service (Egnos) is Aurigny Air Services, which for the past few months has been relying on the satellite-based navigation system to sharpen U.S. GPS and Russian Glonass signals to less than 2-meter (6.5-ft.) accuracy in an effort to reduce flight delays, diversions and cancellations.
“It would take £1 million ($1.6 million) of equipment on the ground to achieve what Egnos can do with avionics and space technology,” says Ken Ashton, an official with NATS, Britain's largest air traffic control agency.
Using a combination of onboard avionics, procedures and pilot training to enable LPV (localizer performance with vertical guidance), Egnos uses three satellites and a network of ground stations to allow aircraft to perform near-precision approaches using vertical guidance.
Interoperable with the U.S. Wide Area Augmentation System (WAAS) and the Japanese Multi-functional Satellite Augmentation System (MSAS), Egnos is a suitable alternative for regional, corporate and general aviation operators working in remote areas and small airports that cannot afford ground-based instrument approach systems that use radio signals and lighting arrays to enable safe landing in inclement weather.
Aurigny recently equipped its six Britten Norman BN2A Mk.III Trislander aircraft with the Egnos avionics upgrade. The company offers the only commercial flight services available on the British Channel Island of Aldernay, a 3-mi.-wide stretch of land situated about 5 mi. off the French coast of Normandy.
“It's the connection to the mainland, and in many areas this is treated very much as a bus service,” Ashton says. In addition to commuter services, Aurigny provides medical flights, business and freight services to the island's 2,400 inhabitants. “So there's a good business case for the operator to become involved in Egnos.”
NATS implemented the new LVP procedures in November 2011, with one Aurigny Trislander aircraft equipped to “pilot” the operation, which was certified by the European aviation safety authority in December 2011.
“The project was to implement an operation—not a trial, not a demo. This had to be done by the book, with an equipped operator and necessary operational approvals to fly Egnos,” Ashton says.
Prior to the satellite-based system, the minimum altitude at which Aurigny's aircraft could approach a runway was 390 ft. with 1,400 meters visibility.
“It is actually quite a significant problem because if they come down in clouds, they have to align the aircraft with the runway to make a successful landing, and its quite a high-workload situation,” Ashton says. “It was an unstable approach, and more importantly it was inaccurate.”
With Egnos, pilots were able to improve their approach to a height of as little as 300 ft. at 900 meters visibility.
“It's both lateral and vertical guidance, so the aircraft is stable on approach,” Ashton says, adding that the current 300-ft. height could be reduced to 250 ft. “Success at Alderney demonstrated we could implement and certify approach procedures, upgrade aircraft and get it certified and get an operator's operational approval to use it.”
In addition to Aurigny, U.K. operators with committed plans to implement the Egnos upgrade include Loganair, Hebridean Air Services, Gama Aviation and Skybus. Ashton says Specsavers Aviation is the first corporate operator to sign on, with plans to upgrade two Beech 350 King Air turboprops for service between the U.K., Ireland, Spain, Scandinavia and the Netherlands.
Two professional flight training organizations, Bournemouth and Aviation South West, are interested in using the system to teach pilots LPV from the outset. Ashton says London Executive Aviation has expressed interest in the system as well.
“LPV capability is on many of the modern business aircraft,” Ashton adds. “They are progressing toward LPV capability.”