Here’s my two bits from a USAF perspective: First, all pins, covers and safing devices are referred to as -21 equipment. Before the first “go”, the intake, exhaust covers and typically data probe covers are removed but all other pins, locks etc. are left installed until just before engine start or even after in the case of the F-16. If weapons are installed, pins remain installed and will be removed at EOR (end of runway) where the jet will not only be armed but checked over for loose fasteners, cut tires, etc. if the jet is carrying AIM 9s, the IR seeker cover and proximity fuse cover are re