Reference to a recent helicopter thread; it is a good idea to know the MSA in the area you are flying in.
If you lose VMC and get into IMC, and a 180° rate one level turn does not get you out of it; you need to have in mind the highest ground or mast that you might be heading towards.
Commercial airliners fly at least 1,000' above MSA unless they are under radar control or are certain of their position and are following published approach or departure tracks. (Certainty of position is confirmed by double or triple IRS, normally with double GPS as well).
For what it's worth, 500' AGL is much too low - give yourself a reasonable safety margin !