Two South Korean air force planes have crashed near Sacheon following a mid-air collision, killing four pilots.

The incident occurred when the aircraft took off from a nearby air base to participate in a training exercise.

Both the jets involved in the accident were KT-1 aircraft, jointly developed by the state-run Agency for Defense Development and Korea Aerospace Industries. This is said to be the first mid-air collision involving two KT-1 jets.

The aircraft crashed in a largely agricultural area and there were no civilian casualties.

At the time of the incident, a trainer pilot and an instructor were aboard each of the jets.

Reuters quoted the air force as saying in a statement: “Despite their attempts at an emergency escape, all of the two student pilots and two flight instructors aboard the two planes died.”

According to the Yonhap News Agency, the black boxes of the two aircraft have already been recovered. This is expected to facilitate the ongoing investigation as the boxes will contain all flight and communications records.

The KT-1 is a domestically developed single engine basic trainer or light attack aircraft designed primarily to meet the requirements of the Republic of Korean Air Force.

Available in five variants, the aircraft has a maximum speed of 648km/h and a range of 1,688km with a service ceiling is 11,580m.

Earlier this year, South Korea grounded its entire fleet of F-35 Lightning II joint strike fighter aircraft following an emergency landing.