The MV-22 Osprey accident last month in Okinawa rekindled concerns about the tilt-rotor aircraft, which was once known as the “widow maker” for those killed during its development.
Starting this year, Japan will see more of the odd-looking hybrids in its skies than the 24 deployed by the U.S. Marine Corps in Okinawa, and residents are worried about potential accidents in densely populated areas and noise issues.
Here are some basic facts and about the Osprey and the lingering issues surrounding it:
What is the Osprey?
The V-22 Osprey is a twin-engine hybrid combining the functions of a helicopter and a fixed-wing aircraft. It usually takes off vertically like a helicopter without a runway and, after its engines are tilted to point forward, can cruise at fixed-wing aircraft speeds, lending to its maneuverability.
It is more capable than the CH-46 Sea Knight helicopters used by the U.S. military in Okinawa and is intended to replace them. They can fly twice as fast as the CH-46, carry three times the payload and fly more than five times farther. Unlike the CH-46, the Osprey can also be refueled in flight, with one refueling giving it the range to reach the Philippines or South Korea from Japan.
Are they safe?
The U.S. military and the Defense Ministry say yes.
During its 25-year development phase, the Osprey suffered four crashes, including three fatal ones. But in September 2005, the Pentagon gave green light for full production, saying it had overcome all safety issues.
Due to its hybrid nature, the Osprey is harder to operate and requires more training than usual, experts say. And the aircraft has had fatal accidents after deployment, including the one in Hawaii in 2015 when two marines were killed in a crash.
When Tokyo announced the introduction of the controversial aircraft in 2012 to gradually replace the aging CH-46s, the Defense Ministry said the Osprey’s Class A accident rate — the rate for accidents that cause property damage of $2,000,000 or more per 100,000 hours of flight — was 1.93.
The ministry apparently used this figure to show the Osprey was safer than other Marine Corps aircraft, which have an average Class A accident rate of 2.45.
But since then, the ministry’s website hasn’t been updated to reflect the Osprey’s current accident rate, which stood at 2.64 as of September 2015. This is slightly higher than the Marine Corps’ average accident rate of 2.63 between 2002 and 2016, according to the ministry.
One factor that has Okinawans worried is that Ospreys deployed to Afghanistan logged 40 times more accidents compared with the average accident rate for all U.S. Marine Corps aircraft deployed in that country, according to Japanese media reports citing statistics between 2010 and 2012 by the U.S. Naval Safety Center.
How did the U.S. handle the recent accident in Okinawa?
Japan’s first Class-A Osprey accident occurred on Dec. 13 when one ditched just off the coast of Nago during in-flight refueling exercise at night, injuring two of its five crew members.
The U.S. military said the accident was not caused by a problem with the aircraft, but by its rotor blades slicing the fuel hose from the tanker plane.
The U.S. grounded all Ospreys in Okinawa after the accident but resumed operations on Dec. 19. The Japanese government also gave a tacit nod to the resumption of refueling drills last Friday, even though the U.S. military has yet to identify what specifically caused the accident. The potential causes cited so far include turbulent air, the complicated nature of in-flight refueling at night, and human error.
Where is the Osprey deployed in Japan?
The U.S. has deployed 24 Ospreys deployed at U.S. Marine Corps Air Station Futenma in Ginowan, Okinawa Prefecture. It also uses helipads in the Northern Training Area in the villages of Kunigami and Higashi in the prefecture. More than half of the training area was returned to Japan at the end of last month, marking the biggest transfer of land since Okinawa’s reversion to Japan in 1972.
The land was returned in exchange for building six helipads on the remaining land, only a few hundred meters away from the Takae district in village of Higashi. According to an environmental review released by the U.S. military in 2012, an annual average of 420 Osprey training flights were projected to be held using the new helipads, but the actual number is not available.
Are there other concerns?
Aircraft noise is an ongoing problem in Okinawa, but Tokyo maintains that the Osprey generates about the same amount of noise as the CH-47 Chinook helicopters used by the Self-Defense Forces.
Last year, 31 residents filed a motion against the central government demanding that a temporary injunction be issued to suspend construction of the helipads, arguing that Osprey training there would jeopardize the livelihood of 150 residents in Takae.
The injunction was rejected last month shortly before the Northern Training Area land was returned to Japan. The Fukuoka High Court’s Naha branch ruled that the noise was within legally permitted levels based on the environmental impact assessment and said there was no proof the noise would severely harm the health of residents.
However, Gentatsu Takamine, one of the plaintiffs, said before the ruling that his family could not sleep during a two-week Osprey training period that included flights at around 8 a.m. and 11 p.m.
“My children cannot go to school due to the psychological damage brought by the Osprey noise,” Takamine said at a news conference at the Foreign Correspondents’ Club of Japan in October.
Will the Osprey be deployed outside Okinawa in the future?
Yes. Three CV-22 Ospreys are planned to be deployed at U.S. Yokota Air Base in western Tokyo this year, and another seven will be deployed by 2021. The CV-22 is the U.S. Air Force version of the aircraft and will be used more to conduct special operations. The MV-22 is the marine version and is mainly used for transport.
Some say the CV-22 could be more prone to accidents because it is used in more severe situations, even during training. The CV-22 is the version that crashed in Afghanistan in April 2010, killing four soldiers. The mileage necessary to calculate official accident rates is not available, but based on some 42,000 flight hours, the air force version has an accident rate of 7.21 — three times more than the marine version.
The SDF also plans to purchase 17 Ospreys by 2018 to be deployed at the Saga Airport after 2019.
As part of bilateral efforts to improve interoperability, the Defense Ministry announced last year that it is going to use the Ground Self-Defense Force’s Kisarazu Air Field in Chiba Prefecture as a joint maintenance hub for the aircraft.
It also has been reported that the U.S. Navy will deploy the navy version of the Osprey between 2021 and 2026, although no official announcement has been made.