COLOMBO: A Sri Lankan Air Force helicopter crashed on Friday, killing six of the 12 people on board, the military said.

The personnel were taking part in a demonstration flight and preparing for a rope jump when their Bell 212 plunged into a lake at Maduru Oya, east of capital Colombo, a military official told AFP.

They had been due to perform a “fast-roping” manoeuvre during a graduation ceremony of Special Forces commandos, showcasing their skills at descending from the helicopter while it hovered above roof height.

“There were 12 people on board, and six of them survived with minor injuries,“ the official said, saying those killed included four commandos and two Air Force gunners.

The ceremony was called off, the official said, adding that an investigation into the cause of the incident was underway.

Friday's tragedy is the worst for the air force since a Chinese-built Y-12 aircraft crashed at Haputale, 200 kilometres (125 miles) east of Colombo, in January 2020, killing all four crew members on board.

In September 2000, an Mi-17 helicopter crashed in central Sri Lanka, killing all 15 people on board, making it the worst helicopter crash in the island's history.