The Air Force has called off a biannual combat exercise involving dozens of warplanes following the crash of a KF-16 fighter jet during a flight mission last month.

A military source told KBS on Monday that the “Soaring Eagle” exercise, previously considered for mid-December, will likely be canceled.

The source said the decision to postpone the training until the new year was made in light of an Air Force order grounding all KF-16 jets, with the exception of surveillance and emergency assets, until the cause of last month’s accident is determined.

A KF-16C jet belonging to the 19th Fighter Wing crashed in the mountainous region of Yangpyeong County, Gyeonggi Province on November 20. The pilot managed to eject safely.

The Air Force has established a safety investigation committee to find out the exact cause, including possible defects in the aircraft.