Mmmm ...
gulliBell ...has pretty much summed it up .... if we assume its a 412 ... then 'stop drill' the crack ... fly the machine back to base TIG weld repair ...
At some stage of our careers we DO have to trust that our engineer brothers know what their doing ... lets try not second guess them!!
Legality should not be an issue if an appropriate entry is made in the 'tech log'.