Depends on the weather. A lot of approaches to airports are GPS only these days. If GPS doesn't work and you are not in VFR weather, you can't fly those approaches. In bad weather you'd be diverting to an airport that still has ILS.

Vectoring by the controller to a visual or ILS approach still works but they'd be juggling a lot of planes. And while lots of the bigger/older airports still have ILS, many VORs and DMEs are being retired and many smaller airports don't have ILS at all.

Denied access to GPS in a large area in bad weather would likely result in lots of flight cancellations and contingency plans getting put in motion to get anything still in the air landed safely. But controllers would get very busy and ILS runways very congested.

Here in Europe, there have been a few cases of GPS denied areas especially closer to Russia. Mostly pilots and controllers at e.g. Helsinki airport are able to deal with this.

lol the very first paragraph of my comment.

But yeah, IFR is getting more dependent on gps approaches…

which is incredibly stupid because it becomes trivial to disrupt air navigation. It’s a bit better with newer chipsets that support GPS, Galileo, GLONASS, and BeiDou… but I’d venture that when the military is jamming I’d does them all. I can buy a jammer that will take out GPS over about a kilometer for less than $1k. They are used all over the place by criminals in many countries, because there often aren’t standardized addresses and if your drug house can’t be located on gps in the favella, you get a lot more warning before a raid. That same transmitter with a directional antenna could knock out a 10 degree sector for 30km.

VMC prevailed at the time of the accident, although it was a dark moonless night. The flight in question only needed to maintain an altitude above the mountains until a visual to the airport was established along with their distance from the runway.

My guess based on the flight path is they had a visual on the airport but were lost and didn’t know where they were. If the gps hadn’t come back on for a minute they probably would have been fine, but it came back on and they fixated on the shiny screen instead of using their navigation skills.

Unless you want trust your life to an instrument, you fly like it might not be trustworthy. Granted, there are many instruments in an airplane we trust our lives to, but they can mostly be cross-referenced against other inputs. The trouble with gps is that it enables procedures that make that essentially impossible, and the major failure mode is not one you can carry an extra for. In aviation, situational awareness is life.