Over the years and specially in the last decade there has been a movement in the aviation industry towards the creation of new route structures and PANS OPS procedures based on Performance Based Navigation (PBN), PBN became a buzzword amongst Air Traffic Controllers, Instrument Flight Procedure Designers (IFPD) and Pilots. Although navigation using Area Navigation (RNAV) has been around at least since the mid 1970’s and from the mid 1990’s GPS RNAV was possible once ICAO made PBN a mandate in 2016 then everything has been revolving around the use of this “new” technology.

Conventional navigation has served the industry well for many decades and it is a known and more or less trusted technology in which each country can buy their own equipment and run flight validation tests once every certain amount of months to make sure that all of the parameters are within the normal working operational margins. The problem with conventional navaids is that they are expensive to maintain specially in big countries, their siting offers quite a few challenges since the radio frequencies on which the trusted VOR, NDB and ILS are based on can be affected by terrain or nearby structures, this requires to put a lot of navaids in the case of mountainous areas or have less efficient routings, also sometimes it is not possible to have certain types of navaids in use like the Instrument Landing System (ILS) at some airports like MHLC (Goloson Intl) or MHTG (Toncontin Intl). Radio navigation aids are also usually situated on high places which kind of makes the aircraft fly over high terrain with the additional considerations to be taken for obstacle clearance. Overall there is less flexibility in terms of the flying direct from one point to the other using the shortest path possible, in essence Europe’s Free Route Airspace (FRA) would not be possible probably.

The typical diagram used to show the advantages of RNAV and RNP over conventional navaids really provides a good statement on what the benefits are, but also you have to consider that it also means that procedures can be designed to airports without any sort of physical navaid on the ground, now of course there are other things to take into account like contingency procedures and if you are not the ownwer of the satellite constellation (most of the world isnĀ“t) then you will need to somehow trust it will not be disconnected. These days there are more than a single constellation as there is GPS, GLONASS, GALILEO, Beidou and also augmentation systems (SBAS) such as WAAS, EGNOS, etc.

Here in Honduras, recently a new airport was comissioned (MHPR – Palmerola International Airport), currently it has no navaid in the ground (tecnically there is a VORTAC but is for military use only and not owned by the Honduras Government). Although the Standard Arrival (STAR) is routed from the North via VOR/DME (Toncontin) this is more of a convenience as the point already exists there but it could have been just a waypoint without use of the navaid of the old international airport. It has been now a few weeks since operations started and every day all of the aircraft glying into and out of this airport do so based only on the published PBN procedures. The truth is with technology we have today there is no need to have NDB or VOR, ILS fall into a different category as not everywhere there is SBAS capabilities. NDB and VOR have served their purpose and are on their way out, NDBs in Central America are almost non existent and the VOR in place are expensive markers that barely are used and on which resources could be saved instead of having a navaid used for less than 100 operations a year. Sure some aircraft still perform some base turns to be able to fly into an airport but that can be solved by using better procedures.

Arrival tracks for one day at the new airport, the more intense it looks the more aircraft follow the same track
With terrain hillshade as backdrop. The turn at the right is done over Toncontin International Airport (MHTG)

We still think the ILS is a fundamental piece of equipment but there is also a need to recognize that with PBN procedures we can open up the possibilities to have instrument flight procedures not only at International Airport or major domestic hubs but every single runway could have an RNP procedure aka RNAV (GNSS), as countries invest in putting this new technologies aircraft operators need to train their pilots and buy aircraft that are capable of reaping the benefits that once were only available for their big brothers at international airports.

Recently a debate over 5G having an impact on aircraft has been in the news, change is inevitable and sooner rather than later aircraft manufacturers are going to figure a way to shield the aircraft from this interference, but the reality is conventional navigation is getting closer and closer to being phased out. Is your country still relying on conventional navaids or has the move to PBN started? Sometimes the local fleet is the one falling behind preventing things to move faster

Update: Thanks to a comment in Linkedin from Nuno Moises, here is Europe’s implementation for 2030 horizon you can check out EU REG 1048/2018 Commission Implementing Regulation (EU) 2018/1048 of 18 July 2018 laying down airspace usage requirements and operating procedures concerning performance-based navigation


flyght7

The webmaster of the Instrument Flight Procedure Design site for FLYGHT7

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