This fix eliminates glitches on taxiways and runways on the grounds of Portland International Airport. Before that, a safe landing was often not possible. This is remedied by leveling/flatten the terrain. I have not observed any effects on the surrounding scenery or flightsimulator at all, but the application of this fix is ​​at your own risk.
Just put the contents of glirem-kpdx-portland-international-airport.zip into the community folder.