Why Airplane Black Boxes Fail
Once more it seems that air crash investigators will face a long, difficult and expensive search to explain the sudden disappearance of an airplane full of people over water—and it need not be this way.
The loss of Malaysia Airlines Flight 370 en route from Kuala Lumpur to Beijing, with 239 people aboard, presents the same challenge faced after Air France Flight 447 disappeared over the South Atlantic in 2009, with the loss of 216 lives.
It took three years, many millions of dollars and a feat of deep sea submarine technology before the wreck of that airplane, an Airbus A330, was located at 13,000 feet below and the flight recorders were discovered.
The fact that today, when vast amounts of data can be streamed in real time, we still rely on tracking down black boxes before being able to deduce the cause of a crash is astonishing.
In the case of the Airbus, it was a matter of sheer luck that that airplane had been transmitting some very basic information—24 so-called fault messages—about its systems before it disappeared. That scant information gave some clues to what eventually turned out to be a series of piloting errors after the airplane’s speed gauges were blocked by ice formed in a high level storm.
The Boeing 777 in this new disaster would similarly have been able to send a few routine data bites monitoring its performance, including how its engines were functioning, information that goes to maintenance centers in case of special checks and spare parts being needed on arrival.
But both planemakers and regulators have resisted repeated calls to adopt available technology to end this dependency on a recording system (and the principle behind it) dating from the 1960s. Indeed, after the disappearance of Flight 447, an exasperated French investigator held aloft a cylinder the size of a small flashlight and said “This is what we are trying to find…in the Atlantic.” In that case it was a sonar beacon intended to lead searchers to a wreck, not the actual flight recorder which is neither black nor a box but about the size of a carry-on duffel.
The principle of the flight recorder was not simply to retain all the data critical to the behavior—or misbehavior—of an airplane, but to entomb it in a casing that could survive the impact of a crash and fire. That principle—that all the vital information should go down with the airplane if it crashed made sense then, but not now.
The point at issue here is not collecting the data. Every modern airliner is keeping track of all its vital systems all of the time in its own data base. The point is to get it out of the airplane in real time, as the airplane is in the air.
Even then, we don’t need to have all the data. Investigators need to see only the data from around 200 sources throughout the airplane to give them a picture of what was going on right up to the final seconds of a failure. The small amount of data that is already transmitted today goes in discrete bursts from the airplane to a satellite and then to the ground.
Resistance to the idea of having a complete real time picture has until now been based on the argument that it would require more bandwidth between the airplane and the satellite. But, given that all the information in a single digital camera picture can be compressed into a Jpeg file, let alone the fact that most of us have enough computer power in our tablets and our phones to run the international space station, this argument is unconvincing.
The fact is that it’s the cost that deters the change, not the technology.
And now we apparently have another major air disaster requiring the familiar saga of pursuing the black box wherever it lies. Right now it’s not clear exactly where the remains of Malaysia Flight 370 and its passengers may rest. For that reason it’s not possible to know how formidable the features of this part of the South China Sea will prove for the searchers. But it is likely that knowing what happened in this case will take many months.