The FAA has scheduled GPS interference testing near San Clemente Island for selected windows November 4–13, 2026—not an uninterrupted ten-day disruption. For Southern California pilots, students and instructors, the important distinction is between the overall date range and the individual periods when GPS signals may become unreliable or unavailable.
The FAA flight advisory, Southern California Tactical Training Range 26-10, Revision 1, lists these windows. Pacific Standard Time is eight hours behind UTC:
November 4 and November 7 each have a window of 0800–1200 UTC, corresponding to midnight–4 a.m. PST on the same dates.
November 12 has a 2200–2359 UTC window: 2–3:59 p.m. PST. The November 13 window of 0000–0100 UTC is also on November 12 locally, from 4–5 p.m. PST. The final window, November 13 at 1800–2200 UTC, is 10 a.m.–2 p.m. PST that day.
Each event may last its entire listed period. The PDF’s published polygon extends from the surface to unlimited altitude and identifies potential WAAS, GBAS and ADS-B unavailability. Consult the full document for its boundaries rather than treating the island as the center of a simple impact circle.
The FAA notice, NOTC5314, was dated October 30; that is the notice date, not the testing start date. It advises pilots to check NOTAMs frequently for possible changes. The published schedule is therefore a reference, not a substitute for current notices.
The FAA Aeronautical Information Manual, section 1-2-4, explains that government GPS tests are geographically limited, coordinated and advertised through GPS/WAAS NOTAMs. Its guidance calls for checking notices along the route of flight. Interference can affect more than a navigation position: performance-based navigation, moving-map position and ADS-B outputs may also be affected.
For preparation, the AIM points pilots toward conventional-navigation planning and applicable aircraft and manufacturer guidance. That background does not establish whether a particular flight can proceed or which equipment will remain usable. Those questions require current information and aircraft-specific guidance, not just the headline dates.
The FAA’s GNSS resource page provides additional pilot and operator material on jamming and spoofing. It is background guidance, not a new November rule. This advisory announces scheduled testing; it does not document interference already observed.
