the pilot must be able to physically see ground or water..........If something is in sight or within sight, you can see it. If it is out of sight, you can't see it. To apply this rule you must be able to actually see the ground or water.
That piece of CASA's advice is bollox, light is an electromagnetic radiation of a frequency that the human retina is able to detect and form an image in the brain. From whence is the ground or water accessing this electromagnetic radiation in order for you to see same? The requirement is to be in sight, not to be able to see. With a half moon the entire moon is in your sight but you can only see half of it, because it's the only bit radiating electromagnetic radiation in the visible spectrum. To be able to see the ground or water the guy is saying you should be able to discern every tree, unlit house, chicken coop, horse and cow, or estimate the wind strength and direction over water by observation of the waves, and what is going to provide the source of illumination, only fly when no cloud and a full moon? Get real. Now if we were able to see in the infra red spectrum different story.
