A gas turbine engine, comprising: a compressor section; a combustor section; and a turbine section, wherein at least one of the compressor section, the combustor section, or the turbine section includes: a mounting plate; a case wall; and a fastener assembly comprising: a leak resistant insert, wherein the leak resistant insert includes: an outer surface; an inner threaded surface opposite the outer surface, the inner threaded surface defining an insert opening configured to receive a fastener, and the outer surface defining an insert end (327; 427) enclosing the inner threaded surface opposite the insert opening; the fastener assembly coupling the mounting plate to the case wall, wherein the leak resistant insert of the fastener assembly is inserted in a case wall hole of the case wall, and wherein the outer surface of the leak resistant insert contacts the surface of the case wall hole to fluidly seal the coupling of the leak resistant insert to the case wall; and wherein the fastener assembly further comprises a fastener inserted through a mounting plate hole of the mounting plate and into the insert opening and coupled to the inner threaded surface of the leak resistant insert, characterized in that the leak resistant insert includes a flange defining a radial protrusion from the outer surface, wherein the flange is located at a midpoint between the insert opening and the insert end (327; 427). a compressor section; a combustor section; and a turbine section, wherein at least one of the compressor section, the combustor section, or the turbine section includes: a mounting plate; a case wall; and a fastener assembly comprising: a leak resistant insert, wherein the leak resistant insert includes: an outer surface; an inner threaded surface opposite the outer surface, the inner threaded surface defining an insert opening configured to receive a fastener, and the outer surface defining an insert end (327; 427) enclosing the inner threaded surface opposite the insert opening; the fastener assembly coupling the mounting plate to the case wall, wherein the leak resistant insert of the fastener assembly is inserted in a case wall hole of the case wall, and wherein the outer surface of the leak resistant insert contacts the surface of the case wall hole to fluidly seal the coupling of the leak resistant insert to the case wall; and wherein the fastener assembly further comprises a fastener inserted through a mounting plate hole of the mounting plate and into the insert opening and coupled to the inner threaded surface of the leak resistant insert, characterized in that the leak resistant insert includes a flange defining a radial protrusion from the outer surface, wherein the flange is located at a midpoint between the insert opening and the insert end (327; 427). a mounting plate; a case wall; and a fastener assembly comprising: a leak resistant insert, wherein the leak resistant insert includes: an outer surface; an inner threaded surface opposite the outer surface, the inner threaded surface defining an insert opening configured to receive a fastener, and the outer surface defining an insert end (327; 427) enclosing the inner threaded surface opposite the insert opening; the fastener assembly coupling the mounting plate to the case wall, wherein the leak resistant insert of the fastener assembly is inserted in a case wall hole of the case wall, and wherein the outer surface of the leak resistant insert contacts the surface of the case wall hole to fluidly seal the coupling of the leak resistant insert to the case wall; and wherein the fastener assembly further comprises a fastener inserted through a mounting plate hole of the mounting plate and into the insert opening and coupled to the inner threaded surface of the leak resistant insert, characterized in that the leak resistant insert includes a flange defining a radial protrusion from the outer surface, wherein the flange is located at a midpoint between the insert opening and the insert end (327; 427). an outer surface; an inner threaded surface opposite the outer surface, the inner threaded surface defining an insert opening configured to receive a fastener, and the outer surface defining an insert end (327; 427) enclosing the inner threaded surface opposite the insert opening; the fastener assembly coupling the mounting plate to the case wall, wherein the leak resistant insert of the fastener assembly is inserted in a case wall hole of the case wall, and wherein the outer surface of the leak resistant insert contacts the surface of the case wall hole to fluidly seal the coupling of the leak resistant insert to the case wall; and wherein the fastener assembly further comprises a fastener inserted through a mounting plate hole of the mounting plate and into the insert opening and coupled to the inner threaded surface of the leak resistant insert, characterized in that the leak resistant insert includes a flange defining a radial protrusion from the outer surface, wherein the flange is located at a midpoint between the insert opening and the insert end (327; 427).