As divers continue to recover bodies from the fuselage of AirAsia Flight 8501, CBS News reports that satellite data has provided new information about the aircraft's final minutes. A steep climb was likely followed by a stall and a rapid descent at 11,000 feet per minute, three or four times the average rate of descent. The last two or three minutes of the flight were terrifying for everyone aboard.
Even if you aren't waiting for search teams to find the remains of a loved one, it is more than frustrating to hear this without understanding the circumstances surrounding the decision to climb. Weather conditions were difficult, we know, and the pilot had asked for permission to change altitude. It took air traffic control two minutes to respond. After that, the plane disappeared.
Two minutes is a long time if you are waiting in line at the grocery store, much less flying in bad weather and experiencing heavy turbulence. We like to think that air traffic control is always in rapid-response mode, responding to requests almost before a pilot has thought to ask the question.
That may not be far from the truth in major hubs, but it could not be farther from the truth in the skies above Indonesia. There, air traffic controllers do not operate with the up-to-date radar that places like Singapore have. In Indonesia, the controllers use a system called procedural separation to keep track of where the airplanes are. That means they calculate the position of each plane, and the proximity to other planes, using information gathered from the pilots.
It isn't exactly the stone age of global positioning, but it can lead to delays -- say, two-minute delays -- in responding to individual requests to change course or altitude. And that's just one of the challenges for pilots and controllers alike.
We'll explain more in our next post.
Source: Carrier Management, "Southeast Asia Pilots Taking Risks in Overcrowded Skies," Jane Wardell and Anshuman Daga, Jan. 3, 2015