China reserves offshore airspace

China has quietly reserved swaths of offshore airspace for 40 days, a step that aviation trackers say looks like a long, unexplained Notice to Air Missions. (wsj.com) Those notices—called NOTAMs—are routine: they tell pilots and controllers where hazards, exercises or restrictions might affect a flight. (icao.int) The NOTAMs cited in recent reports set the vertical limits as “SFC–UNL,” meaning from the surface up to unlimited altitude, which effectively covers every flight level. (easa.europa.eu) A NOTAM does not itself create national sovereignty; it is issued by an air traffic authority responsible for a flight information region (FIR), a part of the sky that one country’s controllers manage even when it lies well beyond their territorial sea. (globaltaiwan.org) That technicality matters because an FIR notice can block civil airliners or force them to ask permission to cross a route, without altering the legal map of who owns the airspace. (aljazeera.com) What makes this instance unusual is scale and duration: the reservations cover offshore polygons and last roughly 40 days, far longer than the few-day NOTAMs typically used for exercises. (wsj.com) Ray Powell, who runs the maritime-monitoring project SeaLight, pointed out that combining SFC–UNL vertical limits with a 40-day window looks less like a short drill and more like a sustained operational posture. (sealight.live) Practically, airlines will treat such notices as constraints on routing: flights can transit if controllers allow it, but carriers may re-route to avoid operational risk, add fuel and incur delays. (aljazeera.com) Strategically, a long temporary reservation performs two tasks at once. It raises the readiness of military units that would operate in the area, and it signals to neighbors and partner states that forces and command-and-control are being postured there. (globaltaiwan.org) Analysts call that signaling part of a broader pattern of “gray‑zone” tactics: measures that stop short of open conflict but gradually change what other states consider normal behavior at sea and in the sky. (globaltaiwan.org) For now, civil traffic appears able to operate around the polygons if given clearance, and China has not publicly linked the reservation to a named, time‑bound exercise. (wsj.com) The detail to watch is plain: the notices run for about 40 days and list their vertical limits as SFC–UNL, a combination aviation watchers say is uncommon and that keeps the area available for activity at any altitude. (wsj.com)