We’ve all heard about “NextGen” air traffic control, but besides the generic guarantee of shorter delays, do we really know what it will do for us? Sometimes the benefits to the traveler aren’t really all that clear, and that’s probably because the actual definition is more of a nebulous catch-all for change than anything else.
Today, I’m going to talk about Required Navigation Performance (RNP), a form of Performance-based Navigation (PBN), and what it can do to help airport arrivals. But instead of defining it in boring terms, I’ll look at a recent implementation high in the Andes to show how you can benefit from it.
RNP allows airplanes to fly precise, complex approaches without the need for any ground-based navigational aids. Today, the use of Instrument Landing Systems (ILS) hampers the ability to run complex approaches in some areas, because difficult terrain prevents these ground-based systems from adequately guiding the aircraft. Consequently, when visibility is bad, some of these airports see serious constraints.
One of those places is Cusco, Peru. Here is a picture I took looking east after landing there last year:
It may not look like much, but consider this. That runway is about 11,000 ft above sea level. It sits in a dead-end valley with only way good way out. As you can see, those mountains go up pretty quickly. And by the way, this view is actually of the GOOD way out of the valley.
Airplanes fly in from the west, descend into the valley, and then do a sharp loop to land back toward the west. It was a fairly dramatic arrival for us, though the clear blue skies made it seem routine. Combine that complexity with gusty winds and fog or rain and you’ve got one incredibly tricky arrival.
In fact, it’s so tricky that you’ll never experience it. When the weather gets bad, flights get canceled. Until now. LAN Peru, the largest operator at the airport, recently finished testing a system from Naverus that allows it to fly an RNP approach into the airport.
The added precision of the RNP approach allows LAN to fly with more accuracy on a very complicated approach, and that means they can land safely in lower visibility situations.
This isn’t a new thing. Alaska, for example, first tested RNP flying into San Francisco several years ago. When the fog rolls in, SFO has to spread out its arrivals because the two runways are too close for comfort using existing systems. Just imagine if SFO could actually operate at normal capacity during foggy days thanks to more precise approaches. Delays would disappear from the airport.
This is just a glimpse of the future. There are other systems that can have similar results, and of course there are other pieces of NextGen that impact other phases of flight. When you hear buzzwords about NextGen and RNP, this is the type of thing that will eventually be possible. If you’d like to learn more, take a listen to this podcast on the subject. (It’s a little dry, but the information is good.)