GNSS Interference: A Growing Threat in the U.S.

Preparing for GNSS Interference During Routine Flight Operations

Article originally published on SM4

What was once considered a threat confined largely to conflict zones has become an increasingly common operational hazard for pilots in the United States. As Global Navigation Satellite System (GNSS) interference continues to increase both within and near U.S. airspace, domestic flight crews must remain vigilant and prepared to recognize and safely manage extended periods of interference.  

Over the past several decades, GNSS has evolved from a convenience to a critical component of modern aviation safety. Today’s aircraft rely on GNSS for aircraft positioning and navigation, instrument approaches, surveillance and traffic awareness, terrain awareness, and runway overrun prevention. When GNSS signals are disrupted—whether by intentional interference or unintentional causes—aircraft must transition to alternative, often less capable, navigation systems to safely continue flight operations. 

GNSS interference generally occurs in one of two forms: 

• Jamming – A signal that inhibits a GNSS receiver from acquiring the intended satellite signal 
• Spoofing – A false signal designed to imitate an authentic GNSS signal while providing inaccurate positioning and navigation information 

According to the International Air Transport Association (IATA), the global rate of GNSS signal loss per 1,000 flights increased 65% in the first half of 2024, compared to the same period in 2023. In June of 2025, the Federal Aviation Administration (FAA) reported an average of 900 daily global spoofing reports. 

While the majority of GNSS interference continues to occur in and around global conflict zones, reports of disruptions are becoming increasingly common during routine flight operations in the United States. Even when interference is unintentional, these events can have significant operational and safety implications. 

On May 14, 2026, a King Air C90 was involved in a fatal accident while on approach to Ruidoso, New Mexico. The Preliminary Report from the National Transportation Safety Board (NTSB) stated that “GPS jamming activities that encompassed the area around the accident were being conducted by the United States military during the time of the flight.” 

Although the preliminary report does not establish the extent to which GPS jamming may have contributed to the accident, the event serves as a sobering reminder that GNSS interference is no longer a distant concern and should be treated as a credible operational risk. 

In March of 2026,  the FAA Flight Technologies and Procedures Division (AFS-400) released an updated resource guide warning U.S. operators and pilots that GNSS interference is becoming more frequent, widespread, and persistent. 

The FAA identifies several potential sources of interference within the United States. The most common causes are military testing and training activities, though interference may also result from law enforcement efforts to counter unauthorized drone operations, naturally occurring phenomena such as solar activity, or from intentional disruption by malicious actors. 

As part of mission planning, flight crews should prepare for the possibility of GNSS interference by assessing associated operational risks and incorporating mitigation strategies and contingency procedures into the formal preflight briefing. Before each flight, pilots should review GPS NOTAMs to identify any planned GNSS interference activities along the route of flight. It is important to recognize that some military GPS interference exercises can affect aircraft operations up to 400 nautical miles from the source. 

Pilots should also be able to recognize the indications of both GNSS jamming and spoofing and be familiar with the aircraft manufacturer’s guidance for operating in environments where GNSS signals may be degraded or unavailable. 

During flight, maintaining situational awareness is essential. Pilots should remain vigilant by maintaining the minimum safe altitude outside of takeoff and landing, continuously cross-checking GNSS-derived navigation information with independent navigation sources such as ground-based navigation aids and inertial reference systems, and promptly notifying ATC if GNSS performance degrades or signal integrity is lost.  

When operating in areas where GNSS interference has been reported, pilots should use ground-based instrument approaches whenever practical and identify nearby Minimum Operational Network (MON) airports as potential alternate navigation and approach options. 

GNSS interference can occur anywhere, at any time, and at any altitude. Staying prepared, recognizing interference early, and reporting GPS anomalies after flight are essential to maintaining the safety and integrity of our airspace.