ΔE 11.8, fair: the same colour family, but not a straight swap. Rus. AF Grey Prot. Coat is a little lighter, more muted than Sky Blue.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Rus. AF Grey Prot. Coat is a little lighter, more muted than Sky Blue.
The same difference applies the other way round: Sky Blue is a little darker, more saturated.
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 Sky Blue on the colour wheel See Rus. AF Grey Prot. Coat on the colour wheel
All matches: Sky Blue equivalents · Rus. AF Grey Prot. Coat equivalents