Plane's axis intersection with another plane

Hi, everyone, What is the best approach to determine if a plane completely covers another plane? I've tried an approach taking into account first plane axis and checking if that axis intersects the surface of the second plane, but this solution doesn't seem to work for vectors that are non-unit. Both planes are parallel and their normal directions are same. I have the following code:

Handle(Geom_Line) geomLine = new Geom_Line(firstPlaneAxis);
Handle(Geom_Curve) geomCurve = geomLine; 
Handle(Geom_Surface) geomSurface = BRep_Tool::Surface(secondSurface.Face()); 

// Perform curve-surface intersection 
GeomAPI_IntCS intersection; 
intersection.Perform(geomCurve, geomSurface); 
bool isDone = intersection.IsDone(); 
int points = intersection.NbPoints(); 

if (intersection.IsDone() && intersection.NbPoints() > 0) { // Intersection found }