Nigeria in the last seven (7) years has made significant investment in the procurement of ground based navigational facilities with over 15new Doppler Very High Omni-directional Radio (VORS), over 15 new lnstrument Landing Systems ( ILS) Category II and Five (5) new Instrument Landing Systems Category III .
The country has also invested heavily inthe deployment of ground communication facilities for Extended Range VHF Voice communication system, as well as a Total Radar Coverage of Nigerian airspace with ground surveillance.
All these are navigational equipment for the smooth take off, guidance and landing of aircraft around the country with accuracy, given the deployment of these navigational facilities.
However, the country has gone a step further in a bid to improve accuracy in approach and landing, improve accuracy in flying (enroute), and improve accuracy in descent profile, as the Nigerian Airspace Management Agency ( NAMA) is deploying the Satellite Based Augmentation System (SBAS) side by side as an upgraded redundancy.
Simply put, the SBAS is an equivalent to global systems adopted by America and Europe, Wide Area Augmentation System ( WAAS) and European Geostationary Navigation Overlay Service (EGNOS) and although a relatively new concept in Africa, West Africa is trying to replicate this system of satellite navigation.
The SBAS capacity was successfully demonstrated on February 1, 2023 as part of the agency’s eventual transition from terrestrial based navigation system to a satellite based system using Nigeria’s NIGCOMSAT-1R Communication Satellite at the Nnamdi Azikiwe International Airport ( NAIA) in view of contingents from navigation service providers Agence pour la Securite de la Navigation Aerienne en Afrique (ASECNA), EURO Control and officials of NigComSat .
Benefits & drawbacks of SBAS
Acting Managing director of NAMA, Mr. Matthew Lawrence Pwajok, who drew a comparison between the satellite and ground based navigational was the major reason the SBAS technology is far better is scope and coverage.
Giving insights on the main differences between satellite and ground equipment, Pwajok explained that the Doppler VORs, ILS’ and other navigation equipment procured over the years are good but the systems are not only expensive to procure, install, calibrate and maintain, but also susceptible to weather, environmental factors, power fluctuations, and cyber threats.
These, he explained, affected ground based navigational equipment’s reliability, availability, integrity and continuity and that the SBAS would mitigate the deficiencies inherent in ground based facilities.
He said,”Now, this is a system that can go off and if it goes off, we should have an alternative. An aircraft that is approaching landing, if the equipment suddenly goes off because of power fluctuation, or an animal crosses it and affects the signal, it should have an alternative. You can’t close the airport because the ground equipment has gone off or because of power or some environmental factors that are affecting it.
Further comparing both satellite and terrestrial systems, he said for satellite systems, some of them have 10cm plus or minus for accuracy as against the ground equipment that can be 100cm left, right and centre meaning the satellite system improves on the accuracy that improves safety, and reduces what is called control flight into terrain( CFIT) rather than turning left or right, it puts you more precise on the approach for landing.
“It reduces workload for the pilots and the air traffic controller and then of course efficiency for the airline, it reduces flight time, fuel consumption,turnaround time for the airline and in the long run improves the profitability for the airline.” Pwajok explained.
Director of Safety Electronics and Engineering Services (DSEES), NAMA Engineer Farouk who spoke to NigerianFLIGHTDECK during the SBAS flight demonstration said the availability the SBAS services will be everywhere within the region unlike the ground based that has defined service volumes outside which there is no coverage, that is, he said,” there is continuity of service and availability is much higher compared to the conventional ground-based system.”
Engineer Farouk who also spoke said,” Its is that the fact that it receives satellite signals it has wider coverage area than Ground Based that serves localized area. “It’s cheaper to deploy than Ground Based equipment. The services is put use mostly in smaller Airports , aerodrome. However, it could be used as redundancy or back up at Major Airports. He also mentioned that private and other smaller airports that cannot afford the deployment of ground based navigational aids can derive benefits with application of the SBAS
ILS’ operates on a principle that for enroute navigation the aircraft needs to follow each ILS, point by point to its destination unlike the satellite where those costly ground installations are not necessary for smooth enroute navigation.
Airlines acceptability of SBAS
Airlines in Nigeria under the aegis of the AON were equally represented at the workshop and the body who spoke officially through its Vice President and Chairman Air Peace, Chief Allen Onyema said that the airlines have observed proceedings of the last three days with a tinge of excitement.
He commended the efforts of NAMA and advantages of the SBAS stressing that airlines in the country would key in to any new technology that that helps them reduce cost .
Onyema said:”I am not a technical person, everything has been said but we are curious with a tinge of excitement on what African Aviation is about to experience. The adoption of SBAS in Africa is something that should be welcome by everybody. We in AON, we pledge our support , we pledge our collaboration to this end.
” I’d like to let you know that Nigeria will not be left behind in the pursuit of safer skies. I am happy it is not mandatory but for us, even if it is not mandatory, if it is going to cut cost for us, if it’s going to enhance safety, we are in for it.”
Pwajok had earlier said the agency will not decommission the ILS’ as it plans to deploy the SBAS side by side as an upgraded redundancy.
“For us, it is not that we are going to decommission the instrument landing system, we want to provide alternatives for our airspace users knowing the technicality of the service that they provide. We won’t want to deny anybody access to an airport because one piece of equipment is not working. We have satellite means of communication, we have terrestrial communication systems. For our surveillance we have a ground surveillance radar and a satellite surveillance. We are providing adequate back ups.
” In some airports maybe we have issues with the ground landing instruments, that will not be enough for them to divert or wait, they can actually use an alternative satellite navigation system to be able to land. It is going to be at the discretion of airlines, we are not going to force any airline to have to fit it in. If you are comfortable with instrument landing equipment, we are going to deploy it and we do that as a requirement to have a backup for every service we provide.
He said, “Some airlines might decide to remain on using the normal system and they might be comfortable and it might be okay for them as long as it gives them assess to the airport for landing and takeoff. They are other airlines that might see this as being more cost effective and rather than having a diversion when something goes wrong, they will rather have a retrofit and install this.
Requirements for SBAS implementation:
On how airlines can access the service of the satellite, he explained that the system would favour airlines and not cost them much to retrofit the signal receiver in their aircraft stating that if the equipment is installed and users unwilling it success becomes limited.Pwajok said for the airborne system for SBAS operations, a Technical Standard Order C145 (TSO C145) is the airborne navigation sensor using the Global Positioning System augmented by Satellite Based Augmentation (SBAS).
He said for the airlines who may be apprehensive to migrate to the new system citing cost,”It is expected that this will not require more than a retrofit because this is an aircraft we have ( King Air 30i) we have not bought any equipment to say it’s going to cost a million dollars, this is a Nigerian aircraft yes we are going to put something on board that would help us receive the signal but whatever we’re adding in terms of retrofitting is going to be minimal for aircraft that have been flying our PBN. It’s not going to be capital intensive. Just a retrofit.” He assured.