Which of the following is NOT a type of RNAV?

The concept of RNAV, or Area Navigation, encompasses various navigation methods that allow aircraft to fly on planned flight paths without the need for direct reference to ground-based navigation aids. Among these methods are GPS (Global Positioning System), DME/DME (Distance Measuring Equipment), and FMS (Flight Management System). Each method utilizes different technology to achieve effective area navigation.

VOR/DME, however, is primarily considered a more traditional navigation method that relies on ground-based navigational aids. VOR (VHF Omnidirectional Range) provides azimuth information, while DME gives distance information. The combination of these two systems does allow for a form of area navigation; however, it is still dependent on specific ground installations, thus distinguishing it from the more advanced navigational technologies inherently designed as RNAV methods.

By recognizing the reliance on ground-based navigation aids present in VOR/DME, as opposed to the entirely satellite-based or integrated systems of the other options, it becomes clear that VOR/DME is not classified as a true RNAV type. Therefore, it is identified rightly as the option that does not represent a standalone RNAV system.