This European Standard specifies the dimensions of the installation holes for headless plugs to EN 3706 for sealing drilled fluid systems. The maximum operating temperature is 200 ℃.
EN 3707:2012 Referenced Document
EN 3706 Aerospace series - Headless threaded plugs, cross recess, in aluminium alloy 5086
ISO 5855-1 Aerospace - MJ threads - Part 1: General requirements