US Navy helicopters may have used Tokyo Skytree for military training: expert

TOKYO -- Amid findings that U.S. military helicopters repeatedly engaged in flights in central Tokyo at altitudes that would be illegal for Japanese aircraft, the Mainichi Shimbun has confirmed two U.S. Navy Seahawk helicopters repeatedly flying close to Tokyo Skytree in the capital's Sumida Ward.

When approached by the Mainichi, the U.S. military avoided giving a clear reason for the flights. One expert analyzed the Navy helicopters' flights as military training using Tokyo's tallest tower, suggesting it is possible that practical training is being held above central Tokyo.

For around half a year beginning in July 2020, the Mainichi observed U.S. military aircraft from multiple 200 meter-class buildings, including the observatory of the Tokyo Metropolitan Government's Main Building No. 1 (at an altitude of roughly 202 meters) in the capital's Shinjuku Ward, which offers clear views of the city.

At about 4:10 p.m. on Aug. 27, 2020, the two Seahawk helicopters came from the direction of Kanagawa Prefecture south of Tokyo, where multiple U.S. military bases are located. They flew above the business district in the capital's Minato Ward, traveled north as they reached the Sumida River area and made a U-turn once they passed Tokyo Skytree. The helicopters made quick turns in figure-eight patterns around Tokyo Skytree several times, passing near the tower's Tembo Deck that stands at a height of 350 meters a total of six times.

The Mainichi observed the two helicopters opening and closing the distance between each other, as well as one helicopter guiding the other. Such maneuvers continued for nearly six minutes, then the helicopters traveled back on the same route toward Kanagawa Prefecture.

Naval Air Facility Atsugi in Kanagawa Prefecture is equipped with Seahawk helicopters, which are carrier-based aircraft, used for anti-submarine patrols and in marine salvage.

Toshiyuki Ito, a professor at Kanazawa Institute of Technology's Toranomon Graduate School and former vice admiral who is well-informed on the U.S. Navy, checked the footage showing the helicopters repeatedly circling near Tokyo Skytree.

"When considering the job of a Seahawk, it's highly possible that they are conducting training flights to find enemy submarines at sea," he said.

According to Ito, Seahawk helicopters drop a small-sized hydrophone sensor called a "sonobuoy" to pick up noise under water, and repeatedly circle the area to collect information in order to detect submarines. Ito says the two helicopters were flying in a similar pattern, and explained, "It would mean that they are training over land when they should be doing so over the sea. If that's being done without permission from the Japanese government and the Tokyo Metropolitan Government, then it's a problem."

Meanwhile, Bonji Ohara, a senior fellow at the Sasakawa Peace Foundation and former Japan Maritime Self-Defense Force pilot who headed a helicopter unit, said that the helicopters "seem like they are training to stand by in the air." U.S. military helicopters have a mission to transport VIPs including the president of the Unites States to a helipad in Roppongi, and apparently adjust their landing time in midair.

"I think they are using Tokyo Skytree, a landmark that stands out, as a sign for the holding point. The U.S. military probably doesn't think the flights are dangerous at all," said Ohara.

When asked by the Mainichi why the flights were being conducted at the time, United States Forces Japan merely explained that "all flights conducted by U.S. Forces are either mission-essential or for training and readiness requirements."

(Japanese original by Atsushi Matsumoto and Hiroyuki Oba, City News Department, and Takahiro Kato, Video Group)