Bad weather caused a Myanmar military plane to crash last month with 122 people on board, state media reported on Wednesday, in one of the deadliest aviation accidents in the country's history.
The Chinese-made Shaanxi Y8 military aircraft plunged into the Andaman Sea during a routine flight from the southern city of Myeik to the commercial hub, Yangon.
Navy ships and fishing boats battled strong monsoon swells in the following days to pull scores of bodies from the waves, most of them the wives and children of servicemen.
Recordings from the black box showed the plane went into a nose dive after icing built up on the wings and a sudden increase in crosswinds caused the engine to stall, state media said.
The plane lost contact with air traffic control roughly half an hour after takeoff from Myeik while flying at over 18,000 feet (5,486 metres), according to previous military statements.
"The accident occurred due to loss of control after experiencing adverse weather that caused the plane to stall... resulting in a nose dive," state media said.
Investigators concluded the crash was "not from any act of sabotage, explosion or engine failure," it added.
It is monsoon season in Myanmar but there were no reports of major stormy weather in the area at the time.
Gerry Soejatman, an independent aviation expert based in Jakarta, said storms high up in the atmosphere that are not visible from the ground can cause ice to form on wings or in engine intakes.
But he added that normally pilots would use a weather radar to avoid such clouds.
"If it is storm clouds, this begs the question, why did they fly into it?" he told AFP.
The black box data were analysed by the investigators from Myanmar and Australia, which has steered the hunt for wreckage from the missing Malaysia Airlines flight MH370.
Its last known location before it went missing in March 2014 en route from Kuala Lumpur to Beijing with 239 people on board was several hundred miles north of where the Myanmar military plane crashed.
The accident is the latest long line of crashes among the military's fleet.
A five-strong crew died when an air force plane burst into flames soon after taking off from the capital Naypyidaw in February last year.
Three army officers were also killed in June when their Mi-2 helicopter crashed into a hillside and burst into flames in south-central Bago.