Chopper crash probe team to look into possible mechanical defects

A military probe team looking into this week's fatal marine chopper crash will focus first on the possibility of mechanical defects, a source said Thursday, after video footage showed rotor blades abruptly flying out of the fuselage shortly after takeoff.

The MUH-1 Marineone, the Marine variant of the KUH-1 Surion helicopter, crashed at a military airport in the southeastern city of Pohang on Tuesday, killing five of the six marines aboard and injuring the other.

Footage showed that the chopper's rotor blades were separated from the body just four to five seconds after takeoff. Given that the pilot was a veteran with around 3,300 hours of flight experience, observers put more weight to technical defects, rather than human error, as the more likely cause of the crash.

"Though there have been various types of accidents and defects found since the Surion helicopter was first deployed in late 2012, there had not been any case in which the rotor blades flew out altogether like this," a military source told Yonhap News Agency, declining to be named.

"(The military authorities) plan to focus on verifying the possibility of defects in its basic design or defects in the chopper body or its equipment," the source added.

Soon after the crash, military authorities launched a joint investigation team involving officials from the Marine Corps, Navy, Air Force, Defense Agency for Technology and Quality and the Army's aviation operations command.

Investigators are also taking note of the fact that the chopper received repair work for some vibration problems right before its test flight. During the flight, it went down from a height of about 10 meters and caught fire.

Some industry sources raised the possibility that there could be a problem with the chopper's initial design.

"There was a case in which a European helicopter, based on which the Surion was designed, crashed after its propellers were taken out," a source told Yonhap. "As the Surion originated from the same fuselage of the European type, the cause of the crash could be similar."

The Korea Aerospace Industries (KAI), a local defense firm, developed the Surion based on the design of the Super Puma, which has been developed and marketed by Airbus Helicopters, formerly Eurocopter.

A Super Puma helicopter crashed due to rotor blade separation in Norway in April 2016, killing 13 people.

The KAI has said that it is ready to offer technological support should the probe team call for assistance. It is expected to seek technological advice from Airbus Helicopters if necessary.

The Marines received the helicopters in January for transporting its service members and equipment. The MUH-1s are the first major aircraft in the possession of the 28,000-strong troops since they were integrated into the Navy in 1973.

The Marines had planned to introduce a total of 28 Marineones by 2023. Following the accident, the Marine Corps and Army have grounded all Marineones and Surions. (Yonhap)