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 a backup system of 585 VORs and approximately 200 designated airports, implemented for IFR aircraft to navigate during widespread GPS outages using non-GPS dependent approaches.
The FAA is reducing the VOR network by 35% (from 896 to 585) by 2025 to establish the MON, ensuring VOR coverage at or above 5000 feet AGL across the contiguous U.S. (outside mountainous areas).
MON is a temporary solution until a more advanced Alternate Positioning, Navigation, and Timing (APNT) system is developed, highlighting the ongoing importance of VOR navigation skills for pilots.

See a mistake? Contact us.

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.