The Jakarta Post
State navigation operator AirNav Indonesia said on Monday that air traffic control had been about to approve AirAsia flight QZ8501's request to take a higher latitude when the airplane with 162 people onboard vanished.
According to AirNav safety and standard director Wisnu Darjono, the aircraft requested permission from Soekarno-Hatta Airport's air traffic control to turn left at 6:12 a.m. to avoid a storm. The request was immediately granted. The plane turned 7 miles to its left flank.
The plane's pilot, Iriyanto, 53, then requested to take the plane higher to 38,000 feet from its position at 32,000 feet.
"Request to higher level," said the pilot, according to Wisnu, to which the air traffic controller replied, "intended to what level?".
The pilot stated that he intended to rise to 38,000 feet but did not explain why he wished to fly higher.
Jakarta's air traffic control then contacted its counterpart at Changi International Airport in Singapore to coordinate the pilot's request.
"It took us around 2 to 3 minutes to communicate with Singapore. We agreed to allow the plane to increase its height but only to 34,000 feet, because at that time AirAsia flight QZ8502 was flying at 38,000 feet," he said.
"But when we informed the pilot of the approval at 6:14 a.m., we received no reply," he said.
At 7:55 a.m., the plane was officially declared missing with a last known position between Tanjung Pandan in Bangka Belitung province and Pontianak in West Kalimantan.
Experts believe that the skies around Bangka Belitung at the time were blanketed by cumulonimbus clouds, a type of cumulus cloud associated with thunder storms and heavy precipitation. (ren)(++++)