On Dec. 28, flight AirAsia QZ8501 crashed into the Java Sea. Staff writer Cole del Charco spoke with Christopher Herbster, associate professor of applied aviation sciences at Embry-Riddle Aeronautical University in Daytona Beach, Florida, to discuss the incident.
Daily Tar Heel: What's the latest update on the AirAsia flight search, from what you know? What does the finding of the plane's tail mean for the investigation?
Christopher Herbster: So, they have located the tail section, although it is not entirely clear how much of the tail section is intact. The Java Sea where the plane went down is a fairly shallow body of water; the area where they’re locating debris is less than 100 feet deep. It’s the rainy season there and there is profound runoff coming off the island all around the sea, creating strong currents which creates lots of silt in the water that is running off the land — that is greatly hampering discovery of the plane.
Visibility in the area is averaging only a meter, making human operations unsafe, and unmanned difficult. One of the questions that is very important to answer is whether the flight data recorders are intact in this tail section, or in another piece of wreckage, or even worse have been dislodged from the aircraft itself and are located somewhere else on the sea floor.
DTH: Are we any closer to finding exactly where the plane crashed? are the currents making that difficult?
CH: Most of the aircraft has not been discovered. The cabin area of the aircraft, where it is presumed that most of the remaining passengers are, has not been located, nor have I heard of any of the wing sections being found. So, the real issue here is that it is a very soft muddy bottom and the wreckage would have sunken partway in.
DTH: Was this a large or small plane? Does size matter when it comes to safety?
CH: This was a standard aircraft; I believe an Airbus A320-200. It is a very capable aircraft used by many countries for both domestic and international flight operations. The aircraft itself is likely to have been capable of most of the potential turbulent conditions it would have found, though you cannot rule out the absolute extreme turbulence. The question of how weather played into this is still pending. We expect that the weather played a part because of the communications just before the flight disappeared, where they were asking for clearance to change altitude to fly around some thunderstorms.
DTH: It's mostly pure speculation at this point, but theoretically, what are some of the possible issues that could have arisen so suddenly with that plane?
CH: Well, one of the very intriguing pieces is that the debris that was found was located very close to the last position of the aircraft, which suggests a very rapid descent from flight altitude to the sea surface. The biggest hazards associated with thunderstorms are turbulence in and around the thunderstorm, potentially lightning or hail — but that’s less common in this tropical environment. Icing would be another significant hazard.
The aircraft was located at an altitude that, from observations that I looked at, could support an icing hazard where the aircraft flies through what’s called super-cooled liquid water, found below zero Celsius because it hasn’t frozen due to the spherical shape of the droplets.
And when aircraft fly through these conditions, ice can build up rapidly on the surfaces of the aircraft. That’s a speculative possible result. It’s also possible that the aircraft was somehow damaged. It’s also possible that the aircraft instrumentation could have been providing misleading evidence, which is similar to a thunderstorm-related accident that happened a number of years ago.
DTH: How often do accidents similar to this occur in the flight industry?
CH: These kinds of accidents are actually quite rare. Most aviation agencies have rules and guidelines that keep aircraft from flying through dangerous weather. Here in the United States, we identify areas of aircraft icing hazards, and we divert aircraft around them in a fairly uniform way. Areas of strong turbulence are avoided, so passengers are not put at risk for injuries just literally bouncing around inside a cabin. Many other countries provide the same kind of guidance to their flight crews that keep them safe. This is a fairly rare experience. It’s an unfortunate event at the end of a year that had a lot of aviation tragedies; many more than normal.
DTH: There seems to be some kind of investigation into whether the airline had the proper permits to run flights on that route. Can you comment on that?
CH: It is not clear what the details of this are, though it does appear that this is an accurate statement. Airspaces that are crowded are often allocated in advance to different airlines for different flights, and this was an example of allocated airspace. But it’s not clear right now as to whether that played a role in another aircraft being in proximity to this one, and creating a reason that they were not allowed to change flight altitude.
DTH: What will the ongoing investigation into the Air Asia flight look like, generally speaking?
CH: The number one goal is to recover the lost souls and to recover the flight data recorders. The flight data recorders are our best opportunity to identify a couple of things, what the aircraft was experiencing, and what the flight crew was doing and talking about in the cockpit at the time of the event. We don’t know if this was an event that the flight crew was challenged with and could not overcome, or if it was an event that occurred suddenly and they had no time to respond. We simply don’t know at this time.
state@dailytarheel.com
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