Originally Posted by
Denti
I worked for the operator that had the first operational approval for GLS in europe. And the same company used both 737NGs and Airbus A320 aircraft. Only the 737 was GLS equipped as it was a no-cost option. Although at some point it was decided to phase out the 737 in favor of a pure A320 fleet, the A320 never got GLS approval with that operator. Once asked why, the management told us that there, at that time (until 2016) there was no cost free option available on the A320, in fact it was only as a retrofit that cost around 250k per airframe. That might have changed, and i would expect it to change with the NEO as GLS/GBAS will be more widely used.
Not because it necessarily saves airlines, money, although it might be, as it can, in theory, allow CAT I/II/III curved approach trajectory. No, because it will save money for airport operators. One installation (with a back up set of of course) can serve several runways at once, obsoleting a lot of singular ILS installations. And of course, since it does not need traditional protected areas and more separation for that reason, higher movement numbers are possible, especially once it becomes low vis certified.
And of course, as long as the relevant signals are compatible, and i believe they are between GPS, Galileo and BeiDou, it can even provide higher reliability for a much lower price. Which of course translates in less delays and therefore saved money. So yes, there is a business case for GLS, actually a quite huge one. Now, we do have the egg/hen problem, but there are several airports that already have it installed, including some mildly larger ones like FRA or ZRH for example, next step is for the airlines to decide to get it installed.
To get to Multi Frequency/Multi Constellation you need an appropriate GBAS ground station and airborne receiver equipment. Apart from the SESAR MC/MF test facilities in Europe, I think the only GBAS systems that are multi Constellation are the NPPF Spectr ground stations in Russia that use GLONASS and GPS.