SGPropertyNode *node = fgGetNode(branch.c_str(), num, true );
_offset_node = node->getChild("offset-deg", 0, true);
_serviceable_node = node->getChild("serviceable", 0, true);
_error_node = node->getChild("heading-bug-error-deg", 0, true);
_nav1_error_node = node->getChild("nav1-course-error-deg", 0, true);
_heading_out_node = node->getChild("indicated-heading-deg", 0, true);
SGPropertyNode *node = fgGetNode(branch.c_str(), num, true );
_offset_node = node->getChild("offset-deg", 0, true);
_serviceable_node = node->getChild("serviceable", 0, true);
_error_node = node->getChild("heading-bug-error-deg", 0, true);
_nav1_error_node = node->getChild("nav1-course-error-deg", 0, true);
_heading_out_node = node->getChild("indicated-heading-deg", 0, true);