ΔE 8.8, close: similar, with a visible difference side by side. Russian AF Grey N.7 is a little darker than RLM 78 Light Blue.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Russian AF Grey N.7 is a little darker than RLM 78 Light Blue.
The same difference applies the other way round: RLM 78 Light Blue is a little 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 RLM 78 Light Blue on the colour wheel See Russian AF Grey N.7 on the colour wheel
All matches: RLM 78 Light Blue equivalents · Russian AF Grey N.7 equivalents