With increasing airspace congestion, Satellite-Based Augmentation System (SBAS) is becoming an extremely valuable technology for European aircraft operators. Approach procedures utilizing SBAS technology are widespread throughout North America as the FAA has focused on its implementation over the past 10 years. The European equivalent, European Geostationary Navigation Overlay Service (EGNOS) has progressed a bit slower over the same time period. That has now changed as European authorities have re-emphasized EGNOS procedures in an effort to maximize capacity in an increasingly crowded airspace. There are now more than 444 EGNOS approaches at over 251 airports, and that number continues to grow.
The following article from the EGNOS Bulletin speaks to the importance and growth of EGNOS procedures from someone who has played an important role in developing the technology as well as flying the procedures. It is re-produced here with permission from the publication.
Talking about EGNOS Benefits with…
David Zeitouni is a Technical Fellow in Boeing Commercial Airplanes. Prior to his current employment, David was the FMS Systems Engineering Manager with Universal Avionics for seven years. He is currently a member of the ICAO Instrument Flight Procedures Panel & the ICAO Performance-Based Navigation Study Group. He also served as a United States Air Force military pilot and graduated from the Air Force Academy.
When did you first hear about SBAS and LPVs in the US?
I previously worked for Universal Avionics. Universal was an early adopter of SBAS technology… we certified the first Part 25 (large aircraft) SBAS and Localizer Performance with Vertical Guidance (LPV) FMS. Working for Universal gave me great experience with SBAS and LPV. We had customers ranging from single pilot aircraft to regional operators. I had direct experience with the benefits and value of SBAS.
What about EGNOS, were you following its beginnings or did you find out about it recently?
While developing SBAS at Universal in the mid 2000’s, I became aware of not just WAAS, but the other operational and in development SBAS. As we developed our LPV capable FMS and SBAS receiver, we conducted interoperability testing with all the SBAS systems (WAAS, EGNOS and MSAS) at the time. The FMS I helped certify in 2007 was interoperable and able to utilize EGNOS when safety of life services were enabled. I’ve been promoting the benefits of SBAS for many years within my organizations and within the industry groups I participate.
As pilot, have you ever been able to fly a LPV approach yourself? If so, what was your experience? Was it as good as everyone says?
In my US military career, I was not able to fly an LPV. The Air Force had not adopted or retrofitted LPV technology onto the aircraft. During development of SBAS and LPV systems at Universal, I was able to fly LPV approaches as a pilot and passenger. I’m hooked. The GNSS augmented approaches (LPV and GLS) are awesome. They provide the precision of Instrument Landing Systems (ILS) without the instability or quirkiness due to interference. So, yes, I think LPV is as good, actually better than everyone says.
We always heard that WAAS was born for general and business aviation which are today their most frequent users. However, Europe seems to be reaching medium size and large airports, which is attracting the interest from regional and commercial airlines. Have you seen any requests for LPV from customer airlines?
It’s true that WAAS LPV was adopted early by the GA and business aviation, but not because there is something special about LPV for GA and business aircraft. Airlines only upgrade equipment when there is a very good business case to do so. The majority of airlines operate to airports with ILS procedures to all the main runways. So, there hasn’t been a great need for airlines to retrofit with LPV. As LPV proliferates with projections for significant increases in coverage areas in the coming years, the business cases are shifting. Airlines that operate to airports without ILSs are also seeing the benefit of LPV. Additionally, having an alternative if the ILS is out of service is a benefit. So, yes, we are starting to see interest for LPV from customers. It’s still sparse, but interest none-the-less.
What will be, in your opinion, the main advantages or benefits of having LPV on transport aircraft?
The advantages will depend upon the operation. For some, it is having a precision approach where no other precision approaches exist. For others, it’s the backup to ILS or the benefits of geometric (non-temperature restricted barometric) approaches. Anytime, an operator can fly a precision 3-D approach instead of a 2-D dive and drive is better/safer.
Any final message for our readers?
In the modern world of consumer electronics where technology changes at a rapid pace, aircraft technology is very slow by comparison. Most commercial aircraft fly for 20+ years and often have minimal changes made to them in their active lifetime. When you consider those facts, getting SBAS and LPV on commercial aircraft is now happening at a quick pace. In a few years, we will look back and see that we did make a rapid change from standard GPS to SBAS quickly by commercial aviation standards. It’s easy to wish it would move faster, but we’re getting there.
Source: EGNOS Bulletin, Issue 26, Q2 2018
Build a Case for an SBAS/LPV Upgrade 
ESSP SAS, the EGNOS provider under the auspices of the European GNSS Agency, offers free-of-charge support to European operators wondering whether an investment in SBAS/LPV capability could make sense from a financial perspective. By means of a Business Case tailored to the aircraft's operations, both in numbers of flights and network of destinations, operators are provided with a new argument to be put on the table at the time of deciding. Learn more about building a case for an SBAS/LPV upgrade, contact your UA Sales Representative
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