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Low-altitude flights by U.S. military helicopters repeatedly observed over Tokyo

  • February 24, 2021
  • , Mainichi , p. 1
  • JMH Translation

By Hiroyuki Oba, Atsushi Matsumoto, and Toshiaki Uchihashi


Helicopters affiliated with the U.S. Forces Japan (USFJ) have repeatedly been seen flying at altitudes of 300m or less over Shinjuku Station. Flights at such altitudes are in violation of aviation regulations for Japanese helicopters. Since July 2020, the Mainichi Shimbun has observed 12 helicopters that were clearly flying at altitudes of 300m or less and five helicopters suspected of flying at such altitudes. Some helicopters flew at altitudes of about 200m over Shinjuku Station, which is the world’s busiest station with 3.5 million people using the JR and private railroads every day. The helicopters barely skimmed over the tops of the area’s high-rise buildings. These flights, which endanger the heart of Japan’s capital, have become commonplace.


Noise issues and low-altitude flights by U.S. military fighter jets have repeatedly occurred in Okinawa, which is home to about 70% of all U.S. military installations in Japan. In the center of Tokyo, noise issues have been reported near the “Akasaka Press Center” (Hardy Barracks) heliport in the Roppongi district of Minato Ward.


To look into the exact nature of these U.S. military flights, the Mainichi investigated USFJ helicopter flights in the Shinjuku area for about six months starting in July 2020, recording data from multiple observation points at an altitude of 200m, such as the observatory of Tokyo Metropolitan Government Building No. 1.


Japanese aviation law designates the “minimum safe flight altitude” over densely populated areas as 300m above the top of buildings within a 600m radius of a helicopter in flight. Aircraft must fly above this altitude by law. This altitude is the height needed to ensure a [safe] emergency landing in case of accident or [mechanical] failure, and it is the standard used by the International Civil Aviation Organization (ICAO).


The Mainichi observed problematic flights above Shinjuku Station on a total of 10 days, recording a total of 17 flights (roundtrip flights were counted as two flights). Helicopters that were at low altitudes while departing from or landing at the heliport in Roppongi, which is about four kilometers from Shinjuku Station, were not included in the count.


The helicopters are thought to be U.S. Army “Black Hawks.” The majority of helicopters flew from the direction of Kanagawa Prefecture, where multiple U.S. military bases are located. In 12 of the 17 flights, the helicopters flew at an altitude lower than the NTT Docomo Yoyogi Building (Docomo Tower; altitude: 270m). In six cases, the helicopters flew at about the same altitude as the Tokyo Metropolitan Government Building observatory (altitude: 202m). In eight instances the helicopters flew directly over Shinjuku Station, with some of the flights barely clearing a 170m-high commercial building connected to the station.


In the remaining five flights, helicopters barely cleared the top of Docomo Tower so it is possible they were flying at altitudes in violation of regulations.


Japan’s altitude regulations are not applied to the USFJ due to a special provisions law on aviation enacted in 1952 based on the Japan-U.S. Status of Forces Agreement (SOFA). The fact that low-altitude flights have become the norm in the capital may spark new debate. The SOFA stipulates a duty to respect Japanese laws, and the U.S. made a de facto apology when a fighter jet was found to have flown at a low altitude in Iwate Prefecture in 2018.


Toshiyuki Kusuhara, Daiichi Institute of Technology professor and former aircraft accident investigator at the Japan Transport Safety Board, said: “Pilots must have advanced maneuvering techniques to fly at low altitudes over urban areas. Human error in flights that violate aviation regulations almost always lead to accidents.” Kusuhara warned that “such flights endanger the lives of people on the ground as well as those of the flight crew.”


In response to the Mainichi’s inquiry, USFJ headquarters said that it “complies with the bilateral agreement established by the Japan-U.S. Joint Committee.” The USFJ did not indicate the specific content of the agreement but commented that “all flights are either mission-essential or for training and readiness requirements.”


The Ministry of Foreign Affairs (MOFA) Japan-U.S. SOFA Division commented that “if it is true that [low-altitude flights have taken place], we want to confirm it with the U.S. military.”


Survey methodology

The Mainichi Shimbun conducted a fact-finding investigation into the flights of U.S. military helicopters from July 2020 to January 2021. A total of 90 weekdays were randomly chosen for the survey, and flights were monitored for three to five hours per day. This means it is possible that there were more low-altitude flights during the period of the investigation than captured by the Mainichi investigation. The survey was conducted from multiple locations in central Tokyo at an altitude of at least 200m, such as the Tokyo Metropolitan Government Building observatory (202m), and from Mainichi Shimbun’s own news-gathering helicopter. A flight was deemed to be a low-altitude flight if it was successfully photographed and fulfilled one of the following two conditions: (1) the helicopter was confirmed to be flying at an altitude lower than a building from multiple observation points or (2) the helicopter was flying below or at the same altitude as the observation point.

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