Plain English Meaning

An older approach procedure that an RNAV-equipped aircraft is allowed to fly by using distance measurements from two or more ground stations to figure out exactly where it is, instead of using the navigation aid the approach was originally built for.

Full Definition

Instrument approach procedures originally designed around ground-based navigation aids that have been authorized for use by RNAV-equipped aircraft using two or more DME stations to compute position. The aircraft's flight management system measures slant-range distances from multiple DME ground stations simultaneously and triangulates an accurate position, allowing it to fly the published approach path without relying on the original primary navaid.