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along the route of flight in case VOR navigation is required at any time. The airway that leads to the ECA VOR lists a minimum en route altitude (MEA) of 3,000 feet, which is the clearance altitude. 

## Calculating Descents with the FMS 

Building a descent with an FMS follows the familiar process of entering the basics of the descent into the system, letting the system do the math, and then reviewing what the system has produced. Most FMS units offer a descent planning or vertical navigation (VNAV) page that allows you to enter the details of your descent. Figure 3-31  shows the VNAV page for one manufacturer’s system. Note that there is an entry for each of the descent planning concepts discussed above. Computers perform the calculations using the same formulas and data. 

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