Borescope plug assembly

A gas turbine engine comprising:

• an outer engine case surrounding a turbine section of the gas turbine engine, the outer engine case disposed about an axial centerline of the gas turbine engine;
• a mid-turbine frame disposed radially inside of the outer engine case relative to the axial centerline, the mid-turbine frame including an interior side and an exterior side, the interior side forming at least a portion of a core flow path through the turbine section, the mid-turbine frame further including a third aperture and a second sealing surface surrounding the third aperture, and the third aperture extending through the mid-turbine frame from the interior side to the exterior side;
• a restrictor pin fixedly mounted to the outer engine case, the restrictor pin in sliding contact with the mid-turbine frame;
• a housing mounted to the outer engine case, the housing including a first housing end, a second housing end, an internal chamber, and a bayonet interface;
• a plug extending through the restrictor pin, the plug including a shaft, a first sealing surface, and at least one tab, the shaft extending between a first shaft end and a second shaft end along a plug axis, the first sealing surface disposed at the first shaft end, the at least one tab projecting radially outward from the shaft relative to the plug axis, the at least one tab disposed within the internal chamber, and the at least one tab configured to engage the bayonet interface;
• and
• a spring positioned within the internal chamber between the first housing end and the at least one tab, the spring configured to bias the plug in an axially outward direction away from the first housing end relative to the plug axis.

A borescope plug assembly comprising:

• an outer case;
• an inner case spaced from the outer case, the inner case including a third aperture and a second sealing surface, the second sealing surface surrounding the third aperture;
• an intermediate wall mounted to the outer case, the intermediate wall positioned between the outer case and the inner case;
• a restrictor pin fixedly mounted to and extending through the intermediate wall, the restrictor pin in sliding contact with the inner case;
• a housing extending between a first housing end and a second housing end, the housing including a plug aperture and an internal chamber, the plug aperture located at the second housing end, and the internal chamber extending from the plug aperture toward the first housing end, the housing mounted to the outer case;
• a plug including a shaft, a first sealing surface, and a circular restrictor, the shaft extending between a first shaft end and a second shaft end along a plug axis, the first sealing surface disposed at the first shaft end, the circular restrictor extending radially outward from the shaft, the circular restrictor positioned axially between the first shaft end and the second shaft end, and the plug extending through the plug aperture with the second shaft end disposed within the internal chamber with the first sealing surface in contact with the second sealing surface and with the plug extending through the restrictor pin;
• and
• a spring positioned within the internal chamber between the first housing end and plug, the spring configured to bias the plug in an axially outward direction away from the housing.