Many of us have memorized the minimum VOR service volumes for various VOR types, Terminal, Low, or High as a part of our training or the training and testing we provide. But those days are changing.

As the FAA navigation system changes to a Minimum Operational Network (MON) with respect to VORs, service volumes and availability of VORs is going to change. With those changes, so will the scenarios that we need to teach, and that DPEs will test on practical tests. Not just for testing purposes, but for practical air navigation purposes so pilots, especially IFR ones, know what resources they have available and how to use them.

The plan for the FAA MON with respect to VORs is intended to be a “reversionary service provided by the FAA for use by aircraft that are unable to continue RNAV during a GPS disruption.” There are lots of technical details here, but the gist is that how we use VORs is going to be changing as we move forward in our navigation system.

Some hot topics that might be great fodder for training and testing include the following considerations:

What VORs are still working?

How can a pilot, a student, or a testing applicant determine what VORs are still in service and able to be used for navigation, or alternate if GPS becomes unavailable is a really important skill to develop. Making sure to understand this and how to resource this is a critical pilot and student skill.

NOTAMs are a pretty critical tool in this process. As many VORs are transitioned out of the system, reviewing NOTAMs about specific navigation sources will be a part of determining if a particular site is useable. Just because it is on the chart doesn’t mean it is useable anymore.

How Far Can I Use a VOR?

Transitioning from the older three type of VOR range system, the FAA is working to make some of the VORs work for longer ranges. With a focus on navigation above 5000’ for the longest ranges, a more traditional 40 NM range will be present at most VORs lower than 5000’ that would be used for approaches if needed. The primary navigation range for most general aviation aircraft will change from a 40NM range to a 70NM useable range with means distanced between two MON VORs will increase from a more historic 80NM between VORs to a 140NM VORs for enroute usage below 18,000’ MSL.

There is lots more to learn, and a bunch more that pilots, CFIs, and DPEs alike need to brush up on as we make this transition. The good news is that there are resources. The bad news is that if you don’t, you are going to be lacking information that might be critically to the safety of flight.

It’s time to do a little new learning and some homework if you are a pilot if you are CFI teaching your students, and a DPE who might be testing applicants on these changes as we go forward. I know some of these items will be working their way into practical tests I give soon!

Here are some more resources you might find useful:

A full-page from the FAA – Navigation Programs – Very High-Frequency Omnidirectional Range Minimum Operational Network (VOR MON) is available to learn more about this transition at – https://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gbng/vormon/

The FAA put out a VOR MON Summer Safety Series Webinar you can check out to learn more about what is happening at – https://www.youtube.com/watch?v=xTJpDe4wIv4

There is also a great article on BruceAir, “FAA Explains the VOR MON Program” that you can check out that talks about charting changes and much more detail about this transition you can find at – https://bruceair.wordpress.com/tag/vor-minimum-operational-network/ 

Want to learn more about the VOR MON? Visit – https://www.faa.gov/air_traffic/publications/atpubs/aim_html/chap1_section_1.html