Aviation experts said on Wednesday (January 21) the crashed AirAsia flight's climb of 6000 feet per minute before it lost contact was unusual but not impossible during severe turbulence.
Their comments came after Indonesia's Transport Minister Ignatius Jonan told parliament on Tuesday (January 20) that AirAsia Flight QZ8501 ascended at a far faster rate than normal during its final minutes, according to radar data, after which it stalled and crashed.
Senior pilot and former president director of Merpati Nusantara Airlines Sardjono Jhony suggested it was no surprise the plane was climbing at such a rate in the midst of bad weather, but that no one should be jumping to conclusions.
"It is possible to have a rate of climb of 6000 feet per minute if you are in a very severe turbulence. And based on what they were asking before they lost contact - that they want to change altitude - I believe at that level, at that level, they're experiencing a turbulence that's why they're not asking for left or right to avoid the weather. So that's just based on my experience, it is not a conclusion," he said during a forum with foreign journalists in Jakarta.
Another aviation expert cited the even higher climb rate made by Air France 447, which crashed in 2009 after a rapid climb and subsequent loss of lift.
"The minister said that the climb rate could go up to 6000 at that time and it's unusual. Yes it is unusual, is it impossible? No. If you look at the case of Air France 447, there were moments where the climb rate was over 9500. Now we know that when you have those kinds of climb rates at those kinds of altitudes, regardless of your thrust level of the engine, that kind of climb rate is not sustainable. And that will lead to a speed degradation that will increase your angle of attack to maintain lift. And once you exceed the critical angle of attack, you stop," said Gerry Soejatman, an independent aviation expert.