You should normally enter an airport here using the offical FAA designation, which is not necessarily the ATA (airline definition). If the airport code is all alphabetic and in the U.S., you should add the prefix "K". So Lambert-St. Louis International Airport is KSTL not STL. The reason for this restriction is that the FAA once named navigation aids with the same codes as the airports! Note that Canadian airports are prefixed with a "C".
Enter an altitude in feet. It is best to use the default altitude unless you have a reason to do otherwise.
High Use V
Airway routes FL180 and above normally use only J ("Jet") routes and other high altitude routes. This can restrict routing since such routes don't usually worry about access to small airports. If your routing doesn't work the first time, try selecting this and low-altitude ("Victor" or "V") routes will be included in the routing.
This does not, as it might seem, determine whether VOR's are used in autorouting. What it determines is whether they are used regardless of their connections to airways. If this is checked, the routing get much more complex and all VOR's anywhere near your route are added into the shortest-path calculation. Unless you are in the flatlands, this is not necessarily a good thing as there can be no guarantee of obstacle clearance and the VOR reception.
If this option is checked, NDB's will be used in the routing equations. Since their range ("service volume") is limited by FAA rules, they are not usually a major help in routing.
Normally the least-path routing algorithm restricts itself to a rectangle defined by the latitude and longitude of the "from" and "to" points, plus 30 nm on either side. This works well except in extreme situations when one-way canyons and various restricted areas make routing difficult (try KELY to KHWD at 12000). If this box is checked, the entire database will be used for routing, which can create some interesting routes, but does take some time.
The FAA airways database includes not only VOR's, NDB's, and named intersections on the airways -- it also includes all other airway crossings and ARTCC boundaries. While these are always used in routing, their display is tedious unless they are needed. This option automatically removes all intersections not used for routing. If the "Use MEA in strip" box is checked, points that define MEA changes are not stripped. If the "Include center boundaries in strip" box is checked, ARTCC boundaries will also be removed.
Use MEA in strip
When stripping a route, if this box is checked then intersections that define MEA changes will not be stripped.
Include center boundaries in strip
If this box is checked, the stripping operation will also remove ARTCC boundaries.
Use default altitude
Except for the Conquest 441, for which extensive performance tables have been entered, the program estimates climb, cruise, and descent parameters using assumptions that may or may not be really valid for a particular aircraft. Therefore, for most plans, especially when comparing aircraft performance, the software works best at the default altitudes entered for the aircraft. If this box is checked, the altitude specified in the form will be ignored and the default altitude substituted.