thanks for the input. i asked four DPE's in my area about their opinion on using a handheld NAV/GPS to meet the PVT Practical Test Standards. the first three gave me vague answers and mechanical questionable requirements (installation of non-TSO'ed "docks") and the fourth said, "no problem, send him over." he was even comfortable with the idea of administering a check ride in the back seat of the pa-18, from which you can't see squat. So i guess it's an area left to interpretation. one would think the more simple the airplane, the more simple the check ride. apparently, that is not the case.