Why can't I use the ZB-500 in Yak-141 from the beginning?

[Crimson_Heron]

When will the study of the ZB-500 modification of Yak-141 be implemented? Or is it just not available when it should be available from the beginning?

[Mahiwew]

It should unlock after researching FAB-500 modules, since it should allows for mountings of all 500kg bomb armaments.

[Gunjob]