Japan Coast Guard helicopter crash off Sanagi Island

The Japan Coast Guard helicopter crash off Sanagi Island (Sanagijima-oki Kaiho heri tsuiraku jiko) was an aviation accident in 2010 (Heisei 22) in which the helicopter “Akizuru” of the 6th Regional Coast Guard Headquarters crashed off Sanagi Island, Tadotsu, Nakatado District, Kagawa Prefecture.

History of the accident aircraft

In November 2007 the accident aircraft was transferred from Kagoshima Air Station to Hiroshima Air Station. At this time, through a public naming contest, the aircraft's nickname was changed in March 2008 from “Rurikakesu” to “Akizuru”, combining the province of Aki and the crane (tsuru).

Overview of the accident

The accident aircraft, “Akizuru” (registration: JA6796, unit designation: MH796), belonged to Hiroshima Air Station (Hiroshima Airport) of the 6th Regional Coast Guard Headquarters in Mihara, Hiroshima Prefecture. “Akizuru” took off from Hiroshima Air Station at 13:47 on 18 August and was scheduled to return after patrolling the Seto Inland Sea and carrying out demonstration flights (described below).

Between patrols for oil leaks at sea, suspicious vessels and the like, “Akizuru” was carrying out demonstration flights for a vessel sailing off Kagawa that was carrying legal apprentices.

“Akizuru” was carrying out patrol duties in the interval before the 2nd demonstration. At around 15:10, while flying at low altitude, the aircraft struck a 6,000-volt power line (total length 1,179 metres, highest point 105 metres above sea level) linking Sanagi Island in the Seto Inland Sea with the neighbouring island of Oshima, and then slammed into the sea surface, broke apart and sank. According to eyewitness accounts, the aircraft had been trying to climb just above the power line with its nose pointed diagonally upward, but suddenly flipped upside down and fell into the sea rotor-first, with smoke coming from its rear. All 5 crew on board were killed in the line of duty.

Aftermath of the accident

Because everyone on board died, the cause of the accident has not been determined, but it is presumed that the captain and co-pilot were not aware of the overhead line and did not see the aviation obstruction lights. The 6th Regional Coast Guard Headquarters was criticised for its shifting explanations of the accident. At first, the headquarters explained at a press conference that the accident had occurred during normal patrol duties, and did not disclose that it had occurred between 2 demonstration flights.

Shortly afterwards it came to light that demonstrations had been carried out, and the mass media criticised the headquarters for trying to “cover it up” and for failing to fulfil its accountability. Consequently, on 3 September the Minister of Land, Infrastructure, Transport and Tourism (at the time), Seiji Maehara, issued personnel orders transferring the head and deputy head of the 6th Regional Coast Guard Headquarters effective 10 September, which amounted in effect to their dismissal.

The wreckage of the accident aircraft was salvaged from the sea area of the accident and brought into a hangar at Hiroshima Air Station on 22 August. The aircraft was kept as evidence at Hiroshima Air Station, and in summer 2011 was moved to a warehouse in Minami-ku, Hiroshima, managed by the 6th Regional Coast Guard Headquarters. After the Takamatsu Coast Guard Office concluded its investigation, it was dismantled in July 2012.

In January 2013, Hiroshima Air Station began preserving and displaying 3 identification plates from the accident aircraft to prevent the accident from being forgotten. They were displayed together with a plate engraved with words such as “We will strive to prevent recurrence”. In April of the same year, the Japan Coast Guard displayed 3 parts of the accident aircraft, the right-side door, the tail rotor and a landing-gear part (cross tube), at the Miyagi Branch of the Japan Coast Guard School as a lesson for the training of pilots and mechanics.