Search and rescue teams located portions of the wreckage belonging to the downed Japanese Air Self Defense Force F-35 Joint Strike Fighter that went missing Tuesday evening. The search for the pilot is ongoing.

At approximately 7:30 p.m. local time on Tuesday, a Japanese F-35A disappeared from the military’s tracking systems somewhere off the coast of northern Japan. It was one of four F-35s flying routing operations out of Misawa Air Base, where the nation recently stood up its first operational F-35 squadron in March. Japan currently operates only 12 total F-35s, down from 13 prior to yesterday’s crash. The nation has current orders with Lockheed Martin to source a total of 147 of the stealth fighters, making Japan the largest purchaser of the air frame aside from the United States.

Search and rescue efforts launched shortly after the F-35’s disappearance, prompting speculation on the internet that the pilot may have veered off course intentionally in an effort to defect with the fifth-generation fighter. However, with three other F-35s in formation with the aircraft, this possibility was never a likely scenario.

Amidst pressing and immediate concerns about recovering the pilot, the discovery of portions of the F-35’s wreckage raises legitimate security issues about wreckage recovery. With both China and Russia working to develop fifth-generation fighters, gaining access to portions of the F-35 could help either nation reverse engineer elements of the aircraft.

China’s stealth program is reportedly more advanced than Russia’s, but the country struggled to field a capable powerplant in its J-20 stealth fighter. So it can be assumed that China has a particular interest in recovering the Pratt & Whitney F135 engine that powered the F-35A that went down. It seems entirely possible that while search and rescue teams continue to operate on and above the surface, there’s likely a flurry of submarine activity ongoing beneath it as vessels from multiple nations attempt to find or protect the state secrets that may be sinking into the depths of the Pacific.

There are currently numerous naval vessels and aircraft publicly involved in the search for the missing pilot and the rest of the F-35’s remains. According to a release from the U.S. Navy’s 7^th fleet, at least one P-8A maritime patrol aircraft and one guided-missile destroyer—the USS Stethem—have joined Japan’s aircraft and ships in the rescue and recovery mission.

This crash is only the second total loss of an aircraft for the F-35 program. Last September, an F-35B (vertical landing variant) crashed near Marine Corps Air Station Beaufort in South Carolina. The pilot was able to safely eject from that wreck.