ΔE 6.0, close: similar, with a visible difference side by side. USAAF Light Gray is more saturated than RAF Light Aircraft Grey BS381C/627.
Usually, if you are not matching paint already on the model. Close match (ΔE 6). USAAF Light Gray is more saturated than RAF Light Aircraft Grey BS381C/627.
The same difference applies the other way round: RAF Light Aircraft Grey BS381C/627 is more muted.
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 RAF Light Aircraft Grey BS381C/627 on the colour wheel See USAAF Light Gray on the colour wheel
All matches: RAF Light Aircraft Grey BS381C/627 equivalents · USAAF Light Gray equivalents