Thanks to all for your contributions to this very interesting discussion. From it, I have learned how to alter the friction factor for a given airfield on a map where I have access to the its load.ini file. However, I use UP 2.1 which includes a number of mod-maps but does not provide, access to their load.ini file, at least, not to my knowledge. Is there a way I can change the friction factor for a given runway in a UP 2.1 mod-map?
If it is a stock map, one of the standard game maps, then I guess there is not much you can do. But with any oter map, you should go to the following folders:
...MODS/mapmods/maps/ ...
where you should find a number of newly added map folders. Open any of the folders and find a file with a title 'load.ini' or something similar, like perhap 'load_summer.ini' or 'load_1024.ini' or some such. Open that .ini file with a text editor and IF that map has friction mod airfields, then all the way at the bottom there should be a section like this:
[AIRFIELDS]
Airfield_001 = 195255.69 87367.9 196193.16 85869.21 2.45
Airfield_002 = 237312.7 124822.63 238725.94 122906.76 2.45
Airfield_003 = 130009.15 29660.79 131956.52 28967.24 1.90
Airfield_004 = 240435.89 129704.28 242005.4 128883.14 2.05
Airfield_005 = 230824.28 45762.61 232511.23 45245.03 2.00
Airfield_006 = 194066.48 53893.92 195366.77 53692.52 2.25
Airfield_007 = 270649.38 164114.98 271647.03 163861.83 2.15
Airfield_008 = 252099.88 47611.69 254196.6 47080.79 2.45
Airfield_009 = 189904.05 28940.25 192319.16 28459.01 2.05
Airfield_010 = 235643.84 21058.39 237523.84 20455.95 2.05
Airfield_011 = 228175.61 68928.28 230003.98 68291.28 2.15
Airfield_012 = 288469.9 22797.55 290139.62 22427.73 2.15
If there is, and if there isn't then the map has no friction mod airfields, but if there is, you can edit the last 3 digits of any line. Standard friction value is 2.45 - and you can go up or down. Down giving less friction and thus an easier landing.
But remember, this works only if the maps already have friction airfields. There are not that many maps at the moment as far as I know. But surely more will be dded.