use of $this

Is it ok to assign data into $data in a Controller using $this in order to make it accessablethrough any method in any "child" controller

Code:

class MY_Controller extends CI_Controller
{
   protected $data = array();
   function __construct()
   {
       parent::__construct();

       $this->data['brand'] = 'myCompany';
.....

And now,  another Controller extends MY_controller. It has a method that loads a view and passes $data to this view, like this:

Code:

$this->load->view('start.php', $this->data);

It's works and it is handy, but is it OK, is it good practice?