SPLINE7 is a 6 DOF beam spline created for mapping loads from a source FEM to a target FEM. It was developed for structure to structure load mapping. However, it will also work for Aero to structure mapping.
There are 3 examples with SPLINE7 delivered in the tpl directory:
\tpl\aero_asm\cyl144b.dat
\tpl\asm3\asm3rlxf.dat
\tpl\ue_2006\ha144a7.dat
For details about Nastran SPLINEs, review this SimAcademy session and attached presentation notes:
A Review of Splining for Aero-Structure Coupling in Aeroelastic Solutions
