Japan’s Air Self-Defense Force lost contact with one of its Northrop Grumman RQ-4B Global Hawk surveillance drones over the Sea of Japan on Tuesday. The aircraft disappeared from radar around 1 p.m. while operating roughly 50 kilometers off the coast of Tottori Prefecture. Debris spotted floating in the area is believed to be from the missing drone, and officials now presume it has crashed. JASDF chief Gen. Takehiro Morita confirmed the aircraft was not on a training mission, though neither the cause of the incident nor the nature of its flight has been disclosed.

The Global Hawk was one of three such high-altitude, long-endurance drones based at Misawa Air Base in Aomori Prefecture. Japan acquired the aircraft from the United States in a 2015 deal valued at approximately $1.2 billion. With a wingspan of about 40 meters and the ability to remain aloft for more than 30 hours, the platforms play a key role in regional surveillance and reconnaissance. The loss reduces Japan’s available fleet to two aircraft and raises questions about the reliability of the system, the circumstances of the flight, and any potential impact on ongoing monitoring operations in surrounding waters.