Backing Up GPS

The MON will remain until an advanced system emerges that can seamlessly recover from a GPS failure. Until 2014 the FAA advanced a system that provides alternate positioning, navigation, and timing (APNT) as GPS provides PNT. In 2015 APNT research was pushed into NextGens far term, 2026-2030. Once the MON is complete, the FAA plans to re-evaluate existing VORs, but at that point, APNT research will just be getting off the ground. The bottom line: some VOR navigation will be with us for years to come. Youd be well advised to keep your VOR navigation skills sharp.

Fred Simonds

Thursday, December 26, 2019 at 12:00 AM ET

Verified

Key Takeaways:

The Minimum Operational Network (MON) is an FAA backup system designed for GPS-reliant IFR aircraft, providing VOR-based navigation to designated MON airports with non-GPS approaches during widespread GPS outages.
The MON initiative involves reducing the total number of VORs to 585 by 2025, while enhancing the service volume of retained VORs to guide aircraft to MON airports from 5000 feet AGL or higher.
Serving as a temporary contingency until advanced navigation systems emerge post-2025, the MON underscores the continued importance for pilots to maintain proficiency in VOR navigation.

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Perhaps you’ve noticed “MON” above certain airports on your low-altitude en-route charts beginning in June 2019. The 200 airports so annotated are specially chosen and sprinkled across the contiguous U.S. (CONUS), identifying them as part of the Minimum Operational Network (MON) of VORs and airports. Those MON airports are also listed in Chart Supplements.

Should GPS go dark, MON airports are planned as IFR safe havens. Each has at least one ILS, LOC, or VOR approach not requiring GPS, DME or, heaven forbid, NDB. A MON airport is rarely more than 100 NM distant. The other part of MON is a downsized VOR network that funnels you to a MON airport from anywhere in the CONUS if you are at or above 5000 feet AGL.