I don't know about this particular deck, but it's not uncommon for the decks to be so small as to make aiming circles useless. 24'x24' is common, and that size deck gives just enough room to get the skids on the platform, with the tail hanging over the edge. Common practice is to put the nose close to the edge, leaving just enough room to walk in front of it. On some of these so-called helidecks, you will still have t/r obstructions on one or more sides, and if you turn the wrong way you're going to hit something, and an aiming circle just puts you closer to the obstacles if you stay in it.