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 confinedlargely toconflict zones has become an increasingly common operational hazard for pilots in the United States.AsGlobal Navigation Satellite System (GNSS)interference continues toincrease both within and nearU.S. airspace,domesticflight crewsmust remain vigilant and prepared torecognize and safely manageextended periods of interference. Over the past several decades, GNSS has evolved froma convenienceto a criticalcomponentof modern aviation safety. Today’saircraftrely on GNSS foraircraftpositioning and navigation, instrument approaches, surveillance and traffic awareness, terrain awareness, and runway overrun prevention.When GNSS signals aredisrupted—whether by intentional interference or unintentional causes—aircraftmust transition to alternative, often less capable, navigation systems to safely continue flight operations. GNSS interferencegenerally occursin one of two forms: Jamming – A signal that inhibits a GNSS receiver fromacquiringthe intended satellite signal Spoofing – Afalse signal designed to imitatean authentic GNSS signal while providinginaccuratepositioning and navigationinformation According to the International Air Transport Association (IATA), the global rate ofGNSSsignal lossper 1,000 flights increased 65% in the first half of2024, compared to the same period in 2023.In June of 2025,theFederal Aviation Administration (FAA)reported an average of 900 dailyglobalspoofing 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 wheninterference isunintentional, 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.ThePreliminary Reportfrom theNational Transportation SafetyBoard(NTSB)statedthat “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 notestablishthe extent to which GPS jammingmay havecontributed 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 of2026,theFAA Flight Technologies and Procedures Division (AFS-400) releasedanupdated resourceguidewarningU.S. operators and pilotsthat GNSS interference is becoming more frequent, widespread,and persistent. The FAAidentifiesseveral potential sources of interference within the United States. The most commoncausesare 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, orfromintentional 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 toidentifyany planned GNSS interference activities along the route of flight. It is important to recognize that some military GPS interference exercises can affectaircraftoperations up to 400 nautical miles from the source. Pilots should also be able to recognize the indications of both GNSS jamming and spoofing andbefamiliar with theaircraftmanufacturer’s guidance foroperatingin environments where GNSS signals may be degraded or unavailable. During flight,maintainingsituational awareness is essential. Pilots should remain vigilant bymaintainingthe minimum safe altitudeoutside oftakeoff and landing, continuously cross-checking GNSS-derived navigation information with independent navigation sources such as ground-based navigation aids and inertial referencesystems, andpromptlynotifying ATCif GNSS performance degrades or signal integrity is lost. Whenoperatingin areas where GNSS interference has been reported, pilots should use ground-based instrument approaches whenever practical andidentifynearby 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 tomaintainingthe safety and integrity of our airspace.
