EGNOS for aviation comes a step closer

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19 December 2011

Aurigny Air Services has completed the testing of a new EGNOS-based system that could greatly improve landing capabilities at small airports around Europe. This means airports can offer greater accessibility and safety without the need to invest in expensive ground-based instrument landing systems.

Just in time for Christmas! ©Peter LihouEGNOS is the European Geostationary Navigation Overlay System, a satellite-based augmentation system (SBAS), similar to WAAS in North America, that improves navigation by reducing errors in GPS data. Since March 2011, the EGNOS ‘Safety-of-Life’ service (SoL) has been certified for use in aviation.

The EGNOS satellite signal allows aircraft to more accurately determine position, reducing errors in GPS data and allowing precision landing approaches without the necessity for expensive instrument landing systems (ILSs).

Earlier this year, Aurigny Air Services, which provides air transport between Southampton and Alderney in the Channel Islands, began flight-testing its new EGNOS-ready avionics. The trials were coordinated by NATS, the UK’s leading air traffic control provider.

NATS and Aurigny received funding for the project through the European Commission's Trans European Networks (TENs) programme, which supports the global International Civil Aviation Organisation strategy to move away from ground-based and towards space-based landing systems.

Speaking about the completion of initial validation flights using an EGNOS-LPV procedure, Aurigny's Flight Operations Director David Rice says, "This is good news for our passengers. The system can utilise information from EGNOS to provide vertical guidance as well as the normal lateral GPS guidance so that approaches to Alderney and Southampton can be made that would perhaps not otherwise have been possible in low visibility.

Changing the playing field

The spectacular cliff-top runway at Aurigny’s home airport in Alderney is unsuitable for ILS installations, but many other regional airports face similar challenges, due to difficult terrain, special weather conditions and awkward radio-wave reflection scenarios.

“Unlike Guernsey, Jersey and other UK airports,” explains Rice, “Alderney and Southampton are either too small to justify the cost of ILSs or terrain issues preclude their use. This new system will be a huge benefit to our Alderney and Southampton operations and we are delighted to have led the way for other small European airfields.”

Aurigny Air Services Technical Director Dick Emery has described the project as “pretty straightforward”. Two of the airline’s six Britten-Norman Trislanders were equipped with Garmin 430W GPS systems, linked to the aircraft’s Century III autopilots. Procedures were developed in accordance with EASA’s AMC 20-28 (LPV operations), and the UK CAA’s Directorate of Airspace Policy produced the navigation charts.

Another member of the consortium, Barcelona-based Pildo Labs, provided equipment to record the initial flight trials and verify the results. Everything was cross-referenced with the Pildo verification equipment, Emery explains. “We only needed to do two flights; it was all within a few feet of where it should be.”

Additional work has included completion of the all-important safety assessment.

Rice says the next step is CAA approval for commercial use of the equipment, and that is likely to happen within a matter of weeks. Once everything is approved, Aurigny will start full-scale pilot training and equipping more of its Trislanders with the EGNOS-ready Garmin equipment.

The end result should be improved operational reliability on an island whose only ground nav-aid has been an automatic direction finder (ADF).

The pilot’s perspective

“Our experience during the trial flights has shown the SBAS approaches to be both accurate and reliable,” says Rice. “Flying the Trislander single crew, the new autopilot-coupled approaches will be a great improvement, reducing the pilot workload.”

Compared with the non-precision NDB approach currently available at Alderney, EGNOS will provide Aurigny pilots with a more accurate approach, giving them better minima, i.e. decision height and runway visual range (RVR).

“These approaches will provide precision-style, ILS look-alike instrument approach procedures at small regional airfields,” Rice explains, “making these airfields far more accessible for commercial operations.”

A pan-European movement

While Aurigny looks likely to become the first carrier to use EGNOS-based landing procedures on actual commercial flights, it is by no means the only example of forward thinking in European aviation.

A number of European air navigation service providers (ANSPs) have been working to develop EGNOS-based procedures for key regional airports. In France, for example, the Direction des Services de la Navigation Aérienne is putting into action a comprehensive plan to implement SBAS landing procedures throughout the country. Approaches to Pau, Clermont-Ferrand and Le Bourget airports have already been published.

Meanwhile, since 15 December 2011, aircraft are now allowed to fly approach procedures with vertical guidance provided by EGNOS at 38 airports in Germany. Permission to use EGNOS in Germany was granted by the Federal Supervisory Authority for Air Navigation Services (BAF). On 9 December 2011, DFS Deutsche Flugsicherung signed an EGNOS working agreement with ESSP, the EGNOS service provider.

Experts say the ball is now very much in the ANSPs’ court. With EGNOS operational, they have to get moving on the publication of landing procedures. Once those procedures exist, operators will want to use them.

But there are still obstacles to the wider adoption of EGNOS landing procedures, such as the multiplicity of airport owners and ANSPs all over Europe. The situation is more complicated in the UK, where even within the country there are multiple ANSPs. Emery says not having one overarching organisation means each airport has to decide for itself what to do about new landing procedures. And not every airport has heard of EGNOS.

Everyone onboard

Aurigny Managing Director Malcolm Hart with Hans de With. ©Donna ReayThe GSA has been playing a leading role in getting the word out about EGNOS for aviation, but its presence at key international aviation events has been as much about gathering information as about dissemination. What exactly do European airport operators know about EGNOS? How are aircraft manufacturers preparing themselves? When will new aircraft be EGNOS-ready?

Air service operators such as Air Nostrum have been providing answers. Already in 2010, the airline announced that all of its new aircraft were to be SBAS- and more specifically EGNOS-ready.

As the biggest regional airline in Spain and one of the larger regional carriers in Europe, Air Nostrum has been a key player in the development of EGNOS for aviation, leading groundbreaking projects such as GIANT, GIANT-2, demonstrating how EGNOS can be used to great effect at regional airports.

The GSA's Hans de With says, "Seeing important regional operators like Air Nostrum putting their full weight behind EGNOS is a very good sign. These are the people who will actually use the technology, turning EGNOS from simply a technical marvel into a real tool with benefits for airports, operating companies and citizen passengers."

“Aurigny has been operating in and out of Alderney for over forty years,” Rice syas. He is convinced that the EGNOS-ready equipment now being installed on Aurigny’s Trislander aircraft will mean improved services and enhanced long-term viability of the company's fleet.

And it looks like others are getting the message. Gama Engineering, one of the companies that helped carry out and certify the avionics modifications on Aurigny aircraft, has now been awarded a contract to fit similar equipment in a Beech 76 Duchess for Professional Air Training in Bournemouth.

“We also provide year-round, 24-hour medical evacuation flights," says Rice, "often in adverse weather conditions, and this can only improve that service too. We are taking a huge step forward.”


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Updated: Jan 17, 2013