Unexplained crashes inspire the first black box, March 17, 1953

-March 17, 2017

The world's first jet-powered airliner, the de Havilland Comet, crashed four times in 1953 and 1954, including three fatal mid-flight incidents that were difficult to investigate.

Australian researcher and fuel expert David Warren was on a committee to assess the problems with the Comet when he realized hearing the cockpit noise could help determine the cause of crashes, so he set out to build what would become the first black box.

Devices had previously been used to record flight data, but they didn't record voices and weren't reusable. Inspired by a miniature voice recorder he'd seen at a trade show, Warren built a device using magnetic recording that was easy to erase and re-record.

Called a "flight memory unit," the first prototypes were finished in 1957 and could record four hours of voice and instrument data on a steel foil. Modern devices use digital recorders and solid-state memory that can be quickly downloaded.

The flight data recorder (FDR) and cockpit voice recorder (CVR) make up the black box used today that is very important for crash investigators, but the aviation industry wasn't quick to adopt the idea because of the privacy concerns that come with recording.

In the 1985 interview below, Warren talks about the struggle to get his invention adopted and his attempts to improve it.

After a 1960 crash, the Australian government began requiring FDRs on commercial airplanes, becoming the first to do so.

The data collected by the first recorders included heading, altitude, airspeed, vertical acceleration, and time, and was housed in crash and fire-proof cases. Today recorders monitor many more parameters that help recreate accidents and analyze problems and responses, and are built to withstand fire, crash impact, and the pressure of being submerged deep in the ocean. Black boxes also include an Underwater Locator Beacon (ULB) that is triggered when it hits the water and will emit a signal for 30 days to help locate them, and are now painted orange to make them easier to find in wreckage.

CVRs pick up pilot and crew communications that can be useful, but also allow investigators to listen for engine noise, warning or emergency sounds, and other sounds made by the airplane before it crashed.

In some instances, black boxes are never found, which has led to a call for further improvement to access data in real time on the ground. A real-time reporting system called ACARS (Aircraft Communications Addressing and Reporting System) is already in place but so far it only tracks basic information and only reports during takeoffs and landings. Some aircraft manufacturers have also started incorporating MP3 players that could be capable of recording over 500 hours of flight time data.

Cars will also be required to have a black box to record speed, brake position, wheel direction, seat belt status, and other data.

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For more moments in tech history, see this blog. EDN strives to be historically accurate with these postings. Should you see an error, please notify us.

Editor's note: This article was originally posted on March 17, 2014 and edited on March 17, 2017.

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