A certified GPS WAAS (such as the optional Chelton/Freeflight available for the Chelton EFIS-SV Sport and Pro) allows for stand-alone GPS navigation and GPS-only approaches for virtually all non-precision approaches.  The value of this should be a no-brainer (ever flown a NDB approach in 20 kts. of wind?).

Our system allows for LNAV and baro VNAV which is a benefit as well.  Currently, there are relatively few LPV approaches published but more and more are coming on line all the time.

Currently, the Garmin 480 is the only LPV device available but the usefulness is limited (kind of like ours was until the FAA released all the GPS overlay approaches.

Expect to see a new Chelton GPS unit soon; then we will have LPV as well.  Until then, use baro VNAV with the higher minimums published in the approach plates. 

Kirk Hammersmith

Direct-To Avionics

www.d2av.com