In fact, the State Plane can be indicated as three different projections: Transverse Mercator, Lambert Conformal Conic, or Hotine Oblique Mercator. The projection used for any given area is determined by a Zone system. These zones are set by state. For example, State Plane for most of Massachusetts is in the 'Massachusetts Mainland' Zone using Lambert Conformal Conic. Meanwhile, New Hampshire - which is its own Zone, uses Transverse Mercator.
Thus, when State Plane is selected as the Projection option when exporting maps from Terrain Navigator Pro, the application will automatically adjust to the actual projection used for the selected Zone. This will be reflected in the progress indicator as the reprojection occurs, as well as the information files, map headers, etc. will indicate the actual projection in use.