The final communications between the pilot of ill-fated flight QZ8501 and air traffic control have been revealed as Indonesian naval vessels moved late last night to check new reports of an oil slick in the search zone.
The strain meanwhile has begun to show on some families, who expressed frustration with AirAsia's chief executive Tony Fernandes and the chief pilot in closed meetings on Monday.
Indonesian state navigation operator AirNav said late on Monday that the Airbus 320-200 captain, Iriyanto, had requested permission at 6.12am local time on Sunday to turn left to avoid a storm.
The request was granted and the plane turned left seven miles. The captain then requested to be able to climb saying: "Request to higher level," according to AirNav standards and safety director Wisnu Darjono, as quoted by the Jakarta Post.
The air traffic controller responded: "Intended to what level?", to which Iriyanto indicated he wanted to go to 38,000 feet.
But there were six planes in the area at the time, another AirNav spokesman said, so, after consulting with the destination airport, Changi in Singapore, air traffic control told QZ8501 it could only go to 34,000 feet.
"But when we informed the pilot of the approval at 6.14am, we received no reply," Wisnu said.
According to earlier timelines, all communication between the plane and Jakarta was lost three minutes later, and at 6.18am, it went off the radar entirely.