ΔE 14.3, fair: the same colour family, but not a straight swap. Flanker Light Blue is a little lighter, more saturated than Longbeard Grey.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Flanker Light Blue is a little lighter, more saturated than Longbeard Grey.
The same difference applies the other way round: Longbeard Grey is a little darker, 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 Longbeard Grey on the colour wheel See Flanker Light Blue on the colour wheel
All matches: Longbeard Grey equivalents · Flanker Light Blue equivalents