ΔE 11.0, fair: the same colour family, but not a straight swap. USAF Brown is a little darker, more muted, warmer than Paratrooper Tan.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). USAF Brown is a little darker, more muted, warmer than Paratrooper Tan.
The same difference applies the other way round: Paratrooper Tan is a little lighter, more saturated, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Paratrooper Tan on the colour wheel See USAF Brown on the colour wheel
All matches: Paratrooper Tan equivalents · USAF Brown equivalents