It belatedly revealed that cracks, 1.2-1.5 centimeters long, were discovered on the upper-left side of the fuselage of eight Surions on May 24. Two weeks later, the Army grounded all of its Surions.

As to the cause, the Army panel confirmed that the "fatigue cracks" are attributable to more weight from the spinning of rotor blades than expected in design, DAPA said.

The committee has called for corrective measures to be completed by October in addition to a regular non-destructive inspection.

The Surion, manufactured by Korea Aerospace Industries, is a twin-engine, transport utility helicopter.

The Army has been using the model since late 2012. The finding of the cracks this time marks the fourth-known technological or crack problem.

It raises concern about a possible negative effect to South Korea's efforts to export the Surion. (Yonhap)