Six members of the Thai air force were killed Wednesday when their military helicopter crashed while on a mission in the insurgency-hit far south, a spokesman said. The UH-1H chopper was on its return journey from Betong district, Yala province, headed to an air force base in neighbouring Pattani province when it smashed into thick forest in Betong just before midday. "All six who were on board the helicopter died in the crash," Group Captain Montol Suchookorn said, adding that the crew consisted of the pilot, co-pilot and four technicians.