Design Con 2015

David Warren’s black box

July 26, 2010

JackGanssle-July 26, 2010

Australian David Warren died last week at age 85. That’s not a name most of us know; I was unaware of his existence until reading the obituary.

But in no small way Mr. Warren contributed to air safety. For he invented the “black box,” the cockpit recorders that adorn all passenger aircraft.

Mr. Warren’s father died in 1934, when David was only 9 years old, in one of Australia’s first serious airplane accidents. No doubt that provided some motivation to the young Warren. He inherited his father’s ham radio, which inspired him to learn about technology, as ham radio has done for so many budding engineers.

But his quest to improve air safety by logging events was rejected by everyone. His boss threatened to fire him if he even talked about his brainchild. Finally in 1954 he published a paper on the idea, and had a working unit a few years later.

As so often happens, at about the same time events conspired to turn his fledgling idea into an industry. In 1956 a Super Constellation collided with a DC-7 over the Grand Canyon, killing 128 people. It was, at the time, the worst air disaster in US history.

The Civil Aeronautics Administration (CAA) had been asking Congress for more money for RADARs and other safety equipment; in fact, that very year legislators cut their budget. But the public outcry made Congress relent, and the CAA morphed into the much-better-funded FAA (Federal Aviation Administration) in 1958. Soon black boxes were required equipment.

By recording the events leading up to an accident, and then relentlessly analyzing the data and other supporting information, officials created a feedback loop. Lessons learned from each accident leads to ever-better safety. While every crash is a tragedy, the ashes give life to others.

In the 50s, pre-recorder, the accident rate for commercial aviation was in excess of 50 incidents that involved death or destruction of the aircraft per million departures. Now the number is practically unmeasureable. Air travel is the safest form of transportation, which is wonderfully ironic considering the extremely hostile environment at 40,000 feet and our utter reliance on a wealth of extreme technologies.

Wise developers understand the power of feedback loops. Some - not much - of the code I read includes logging features that store unexpected events for later analysis. Given that we know software is awfully hard to get right, if one has the resources such logging should be de rigor. Alas, it’s not.

Mr. Warren never made a dime on his invention. But generations of travelers owe him a dept of gratitude for it.

Jack G. Ganssle is a lecturer and consultant on embedded development issues. He conducts seminars on embedded systems and helps companies with their embedded challenges. Contact him at jack@ganssle.com. His website is www.ganssle.com.

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