Military GPS Interference Testing Near Wellton Could Disrupt Signals Through April

GPS signals near Wellton have been unreliable since March 31 and will remain so through April 24, as Marine Corps Air Station Arizona conducts planned military interference testing across a zone centered on the BZA VOR 081-degree radial at 20 nautical miles, near coordinates 32°44'15"N, 114°12'17"W.

The testing falls under Test, Training, and Evaluation activities designed to prepare military units to operate in degraded-navigation environments. MCASAZ published the formal flight advisory through FAA/FAASafety channels in late March, explicitly naming Wellton as the local reference point and urging anyone flying in or near the area to pull Notices to Air Missions before departure. Those NOTAMs are required to post at least 72 hours before each individual test window opens.

For general aviation pilots operating out of Yuma-area airports, the immediate concern is GPS-dependent instrument approaches. Precision navigation and ADS-B performance are both potentially affected during active windows. Pilots are advised to plan alternate navigation methods and to communicate any concerns to air-traffic facilities directly.

Drone operators and UAS service providers face the same exposure. Any unmanned system relying on GPS for positioning, geofencing, or return-to-home functions sits within the risk window, making manual override capability essential for any flight conducted in the Wellton corridor through late April.

On the ground, Yuma County's precision agriculture operations are the most likely non-aviation casualty. Auto-steer and guidance systems common on farm equipment depend on WAAS-enabled GPS receivers that can show degraded performance without warning during active testing. Surveying instruments, location-based services, and GPS-synchronized timing systems could all be affected the same way.

Motorists using phone navigation on Interstate 8 near Wellton should expect map applications to occasionally misplace or lose their position.

Pilots and operators with concerns can contact FAA Flight Service or reach MCASAZ directly. The full advisory, including exact coordinates, geographic boundaries, and all testing dates, is available through the FAA Safety Team.