An engine includes a compressor having a first compressor, a second compressor, and a static hub transition duct. The first compressor includes a rotatable portion and a static portion. The second compressor is disposed downstream of the first compressor and includes an inlet and a rotatable portion. The static hub transition duct includes an inner wall and an outer wall. The inner wall is secured to the static portion of the first compressor, and the inner wall and outer wall define a space that fluidically couples the first compressor and the inlet of the second compressor.