A fatal military helicopter crash in July has been attributed to defects in the process of manufacturing some of the choppers key components. 

A joint committee consisting of government and military inspectors and civilian experts on Friday announced the result of its investigation into the crash of the MUH-1 Marineon, which killed five marines who were on board shortly after takeoff in the southeastern city of Pohang on July 17th.

The committee said the rotor mast, which connects the rotor blades with the motor gear, was broken due to cracks, causing the rotor blades to separate from the fuselage. 

The inspectors said the cracks occurred because the components were supposed to be produced through an air-cooling process but instead was manufactured through a water-cooling process. 

They said Airbus Helicopters, the manufacturer of the components, acknowledged the errors.   

The committee plans to inspect why those components were able to pass quality tests and come up with the measures to thoroughly guarantee flight safety to prevent recurrences of similar incidents.