Two South Korean fighter jets crashed mid-air after their pilots started taking photos and videos with their phones, officials have revealed.
The collision took place while the planes were on a flight mission over the city of Daegu.
The pilots survived with no injuries, but damage to the planes cost the military the equivalent of £440,500 in repairs.
Seoul's Audit and Inspection Board has said the crash five years ago happened because one of the pilots had wanted to take photos to commemorate his last flight with his military unit.
The report, which was published today, said that taking photos on milestone flights was 'a widespread practice among pilots at the time', and noted that the pilot had declared his intention to do so in a briefing before the flight.
He had been flying the wingman aircraft and was following the lead aircraft during the mission, but while flying back to their base, he started taking pictures on his mobile phone.
The pilot of the lead aircraft then asked another airman on his plane to film a video of the wingman aircraft.
The wingman pilot then flew his jet up higher and flipped it so that it could be better captured on camera.
The crash involved two F-15 fighter jets. File photo: F-15K fighter jets from South Korea's airforce pictured during an exercise in 2016
But this manoeuvre brought the two planes very close, and to avoid a crash, the lead aircraft was forced to descend rapidly.
However, the two F-15K jets eventually collided, damaging the lead aircraft's left wing and the wingman aircraft's tail stabiliser.
South Korea's air force suspended the wingman pilot following the incident, but he has since left the military to work for a commercial airline.
The air force also sought to fine him 880million won, around £400,000, to cover repair costs.
The pilot appealed against the fine, prompting an investigation by the audit board.
He acknowledged that his sudden movement led to the crash, but claimed that the lead aircraft's pilot had 'consented' to him making the manoeuvre.
The audit board has since ruled that the wingman pilot should only pay a fraction of the fine, and said that the air force should bear some responsibility for not regulating pilots' use of cameras and phones.
The board also noted that the wingman had a good track record before the incident.
It is unclear if any action was taken against other pilots involved in the incident.