Authorization Required
You can do a lot with an instrument rating and appropriately equipped aircraft-slice through clouds, take-off zero-zero and fly VOR, ILS, GPS and even (if you care) NDB approaches. None of these operations require special qualifications beyond the instrument rating. For example, many of us got instrument ratings before GPS, yet were authorized to fly GPS approaches. But, there are things an instrument-rated pilot cant do, even with certified equipment. Wanna fly a CAT II approach? Sorry. How about an ILS CAT I SA or RNAV (RNP)? Nope, cant do those either. What gives?