Document
OAS-43A (12/12)
Interagency Aviation
Accident Prevention Bulletin
No. IA APB 26-07 July 17, 2026 Page 1 of 2 Subject: GPS Interference Testing Area of Concern: Flight Safety Distribution: All Aviation Operations On May 14, 2026, a Beech King Air C90 air ambulance crashed near Lincoln/Ruidoso, New Mexico, resulting in four fatalities. The National Transportation Safety Board preliminary report ( WPR26FA186 ) confirms that active U.S. military GPS‑jamming was occurring in the area at the time and may have contributed to the crew’s loss of navigation capability.
The U.S. military and the Federal Aviation Administration (FAA) routinely conduct planned GPS interference activities, including jamming and spoofing tests to support training and national security. These activities can degrade or disrupt GPS reception for aircraft operating within and near the test area. Testing is coordinated among the Department of War, FAA and the U.S. Coast Guard Navigation Center (NAVCEN) and may temporarily impact navigation, ADS ‑ B position performance, and GPS ‑ based situational awareness.
Both conventional aircraft and UAS are affected. These activities can cause weak reception, loss of GPS navigation, or unexpected alerts in the cockpit or Ground Control Station (GCS). GPS outages can happen suddenly and may affect navigation, ADS-B position reporting, mapping systems, or overall situational awareness. For UAS, GPS interference may degrade the aircraft’s integrated GPS/INS capability, resulting in reduced navigation accuracy and degraded autonomous flight performance. Capabilities such as geofencing, autonomous navigation, lost-link/return to home functions, obstacle avoidance and photogrammetry functionality may be lost.
Why GPS Testing Is Increasing GPS jamming and spoofing events have been rising worldwide, including unintentional interference in the United States. Because GPS signals are weak and easy to disrupt, the FAA and military conduct more frequent testing to prepare crews, evaluate equipment, and strengthen system resilience against these threats.
This testing helps ensure aircraft can safely continue operations even when GPS becomes unreliable or provides incorrect information.
How to Know When Testing Is Happening • Check FAA NOTAMs for GPS interference advisories.
• Review FAA Safety Team (FAASTeam) notices, which often announce upcoming test periods.
• The U.S. Coast Guard Navigation Center (NAVCEN) posts planned GPS testing and interruption notices.
• GPS.gov lists planned disruptions and GPS status information.
No. IA APB 26-07 July 17, 2026 Page 2 of 2 Get Email Alerts • Sign up for NAVCEN GPS status and disruption emails.
• Subscribe to FAASTeam SPANS notices to receive GPS interference advisories automatically.
What Pilots and Dispatchers Should Do • Make GPS interference NOTAM checks part of your normal preflight activities.
• Review alternate navigation options in case GPS becomes unreliable.
• Ensure your situational awareness includes minimum safe altitudes (e.g., MEF, MEA, OROCA, MSA, ESA).
• Monitor for unusual GPS behavior and report issues to ATC.
• If GPS loss affects safety, notify ATC immediately—they can request testing be stopped for safety-of- life missions. When able, report to dispatch who in turn can then to report to Air Route Traffic Control Center (ARTCC).
If you suspect GPS interference (jamming or spoofing or testing) during flight, take these steps: • Cross-check your position using non-GPS navigation and visual cues.
• Watch for abnormal GPS behavior like loss of satellites, map shifts, or RAIM alerts.
• Tell ATC immediately and request vectors or support.
• Switch to backup navigation methods and be prepared to fly without GPS.
• Maintain situational awareness and verify information with available instruments.
• Report the event to ATC and appropriate GPS anomaly channels after landing.
Summary The Pilot in Command is always responsible for maintaining situational awareness as to the aircraft’s location despite system failures and anomalies. GPS interference testing is routine and increasingly important. Staying informed and preparing for potential disruptions helps ensure safe and smooth flights.
Reporting suspected GPS interference is encouraged, even though malicious spoofing or jamming is rare in the continental U.S. Timely reports help authorities identify the source of interference, whether illegal devices, faulty equipment, or natural space-weather effects such as solar flares or geomagnetic storms.
Reporting will support maintaining a reliable GPS signal for all users.
Government Resources • FAA NOTAMs: https://notams.aim.faa.gov/notamSearch/nsapp.html#/ • FAASTeam Notices (GPS Testing Advisories): https://www.faasafety.gov/SPANS/notices_public.aspx • U.S. Coast Guard NAVCEN GPS Interference Notices: https://www.navcen.uscg.gov/gps-service- interruptions • GPS.gov Outage & Status Reports: https://www.gps.gov/gps-service-outage-status-reports /s/ Keith C. Raley /s/ Lori Clark Keith C. Raley Lori Clark Division Chief, Aviation Safety and Training Branch Chief - Aviation Safety Management Aviation Operations and Management Systems U.S. Wildland Fire Service USDA, Forest Service U.S. Department of the Interior