it is especially important to be very proficient with the menus,  functions, and “switchology” of a particular unit. If the  aircraft is equipped with an autopilot, it is also essential to  have a thorough understanding of how the autopilot interacts  and interfaces with the FMS/GPS navigation equipment. The immense capability of the FMS/GPS may tempt you  to follow its directions rather than fly a missed approach  procedure exactly as published on the instrument approach  procedure chart. Always fly procedures as published,  especially with respect to the initial climb and turn  instructions. GPS as a line‑of‑sight navigation aid can display  courses and distances to a ground‑based navaid even though  the navaid is on the other side of a mountain range and itself  cannot be received, because GPS signals are spaced based. The second fundamental skill is displaying indications from  a ground‑based radio navigation facility on the navigation  display indicator in the aircraft. In addition to setting the  navigation indicator to display indications from different  navigation sources, you must also know where to look  to double‑check which indications are currently being  displayed. It is crucial to remain constantly aware of the  navigation source for each indicator. Many systems use color  coding to make a visual distinction between different RNAV  navigation sources (GPS, INS, etc.) and ground‑based radio  navigation sources. Looking at the two systems shown in  Figure 3-59,  you can  see that two VOR frequencies appear in the active windows  at all times, regardless of whether VOR or GPS is being used  as the primary navigation source. To maximize situational  awareness and make best use of this resource, it is a good  practice to keep them tuned to VOR stations along your route  of flight. If you have two navigation indicators, you can have  one indicator set to show GPS course indications, with the  other to show VOR indications. Used in this way, VOR and  GPS can serve as backups for each another. Flying a precision approach requires tuning the required  frequencies, configuring the navigation indicator to display  localizer course indications, and flying the approach. For  aircraft equipped with multiple navigation radios, the  localizer frequency can go into one receiver, while a second  navigational facility used as a cross‑radial can be set in the  other receiver. As you come within range of the localizer and  glideslope, the course deviation and glideslope indicators will  show position with respect to the localizer and glideslope. Most advanced avionics systems include receivers for  conventional radio navigation signals from VOR, localizer,  and glideslope transmitters. To display these signals on the  navigation display indicator(s), you need two fundamental  skills. The first fundamental skill in ground-based radio navigation  is tuning and identifying a ground‑based radio navigation  facility.  Figure 3-59  illustrates how a VOR station can be  tuned using two different systems. Nonprecision approaches such as VOR, localizer, and LDA  approaches are flown using the same procedures used to  fly a precision approach. If the aircraft is equipped with an  autopilot, be sure to develop a thorough understanding of  how the autopilot works with the FMS. While these systems  automate some tasks, others (e.g., flying the procedure turn  course reversal) maybe left to the pilot. Some systems automatically attempt to identify ground‑based  radio navigation facilities that are selected by the pilot. Note  the identifier that appears beside the selected frequency in the  upper left corner of the PFD in  Figure 3-59  (116.00 = ECA). 3-42 Flying a Nonprecision Approach Using Ground- Based Navigation Facilities Tuning and Identifying Radio Navigation Facilities Ground-Based Radio Navigation Configuring FMS To Receive Ground-Based Radio Navigation Signals Flying a Precision Approach Using Ground-based  Navigation Facilities Essential Skills Awareness: Using All Available Navigation  Resources Displaying Radio Navigation Signals on the  Navigation Indicator Common Error: Noncompliance With Initial  Missed Approach Instructions 1. Acknowledge a missed approach procedure. 2. Set the FMS/GPS for a return to the same approach  to fly it again. 3. Select a different approach while holding at a missed  approach holding waypoint. 4. Program an ATC specified hold (user waypoint) point  for selection after the published MAP/hold procedure.