What was found
(CAN) DURING ROUTINE MAINT, RIGHT ENGINE UPPER FWD COWL HAD BEEN REMOVED. DURING CLOSE UP, ENGINEER RESPONSIBLE FOR CLOSURE OF COWL INADVERTENTLY SECURED EACH OF 4 CAM-HOOK ASSY TOWARDS RELEASED POS. SHORTLY AFTER TAKEOFF, COWL SEPARATED FROM ENGINE, STRUCK RT AFT FUSELAGE AREA & GLANCED OFF VERTICAL STAB.FOLLOWUP REVEALED SEVERAL ITEMS: 1) "FEEL" OF CAM-HOOKS IS VERY SIMILAR IN BOTH DIRECTIONS OF OP. 2) DUE TO THE CAM-HOOKS BEING MIRROR IMAGE OF EACH OTHER ON RESPECTIVE SIDES OF COWL, CLOSING & OPENING DIRECTION ARE REVERSED FOR EACH SIDE. 3) UTILIZING RACHET ASSY FOR MANIPULATION OF HEX BOLT ARTIFICIALLY COVERS OPAL ARROWS P RINTED ON HEX BOLT HEAD.CHANGES TO OPE