ΔE 10.4, fair: the same colour family, but not a straight swap. USAF Tan is noticeably darker than US Desert Tan.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). USAF Tan is noticeably darker than US Desert Tan.
The same difference applies the other way round: US Desert Tan is noticeably lighter.
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 US Desert Tan on the colour wheel See USAF Tan on the colour wheel
All matches: US Desert Tan equivalents · USAF Tan equivalents