ΔE 11.5, fair: the same colour family, but not a straight swap. Tan Earth is more muted, cooler than RLM 79 (1942).
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Tan Earth is more muted, cooler than RLM 79 (1942).
The same difference applies the other way round: RLM 79 (1942) is more saturated, warmer.
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 RLM 79 (1942) on the colour wheel See Tan Earth on the colour wheel
All matches: RLM 79 (1942) equivalents · Tan Earth equivalents