Pilots of two South Korean Air Force fighter jets were taking selfies and filming during their flight moments before the planes collided, investigators have found.

In December 2021, the two South Korean Air Force F-15K fighter jets collided with each other during a training mission. The pilots ejected from the planes with no injuries, but the collision damaged the aircraft badly, costing 880m won (£4,40,639) to the military in repairs.

For one of the pilots, it was the last flight with his unit and he took pictures to commemorate it, the government’s Board of Audit and Inspection said in a report. He had even told his colleagues in a pre-mission briefing that he intended to take pictures.

After the flight mission in the central city of Daegu, as the planes returned to the base, the wingman, who was flying the second plane behind the lead pilot, began taking pictures with his phone. The pilot of the lead aircraft then asked another pilot on his plane to film a video of the wingman aircraft.

The wingman aircraft then abruptly flew higher and flipped the plane for the camera. The manoeuvre brought the two planes too close to each other.

To avoid a collision, the lead pilot attempted to rapidly descend while the wingman pulled nearly straight up, causing the collision.

The lead pilot’s left wing clipped the wingman’s stabilator – a movable horizontal tail surface on an aircraft that combines the functions of a stabiliser and an elevator. The lead aircraft’s left wing and the wingman’s tail stabiliser were damaged.

South Korea’s air force suspended the wingman pilot after the crash, who has since joined a commercial airline.

The wingman pilot was fined 880m won to cover the full amount of the repair costs. But the pilot challenged the fine before the board. He admitted negligence but said he was not financially liable for the aircraft as he did not violate his duty of care.

He said the lead aircraft's pilot had "tacitly consented" to the manoeuvre since he was aware that filming was taking place.

The board eventually asked him to pay one-tenth of the bill, reducing the fine by 90 per cent and asking for a reimbursement of approximately 88 million won (£44,063).

The agency defended the decision, pointing to the routine practice of taking commemorative photos during flights and the air force’s failure to regulate it.

“Those who were involved in this case stated that this was not the only flight during which photos were taken,” it said.

The board also highlighted the pilot’s skilful handling after the collision, which prevented further damage, as well as his long service record.

On Thursday, South Korea's Air Force apologised for the accident and said it was taking steps to tighten flight safety rules and prevent a repeat of the incident.

An air force spokesman said in a press briefing: "We sincerely apologise to the public for the concern caused by the accident that occurred in 2021."

He added that one of the pilots involved had been suspended from flying duties, received severe disciplinary action, and has since left the military.

The audit board did not reveal the names of the pilots and did not say if the lead pilot faced disciplinary action.