Using memory to piece together the parts

Thinking recently about the tragic airplane crash over South America involving a Brazilian football team, these accidents are often left unanswered, and the number of them seems to be increasing, especially in mass transit, and sometimes any clue is helpful.

Digital clues left behind in flash memories of electronic devices are very useful and often relied upon, when investigating mass transit accidents, especially in air travel, by National Transportation Safety Board (NTSB) officials.

Both personal and professional electronic devices can hold clues at a crash site. However with the physical forces and high-temperature fires associated with many crashes, memory units are often damaged and sometimes unreadable.

Researchers at Binghamton University, State University of New York have figured out how much damage memory units can sustain before becoming unreadable and new repair techniques to retrieve clues off of damaged units, which might help prevent future tragedies.

Electronic devices

Project Manager and Senior Research support specialist in the Integrated Electronics Engineering Center (IEEC) at Binghamton University, Steve Cain said: “The biggest surprise was how much punishment these devices can take before ceasing to function.”

Cain added: “As part of their post-crash investigations, the NTSB collects anything and everything at the scene, including personal electronic devices. If the device was active during or just before the crash, it is possible that the data stored in the memory can provide clues as to the cause of the crash. Most of the time the device is ruined, but sometimes it is intact.”

The interdisciplinary Binghamton group of Cain, Preeth Sivakumar, Jack Lombardi, and Mark Poliks along with James Cash, Joseph Gregor, and Michael Budinski from the NTSB, presented ‘Fire Damage and Repair Techniques for Flash Memory Modules: Implication for Post-Crash Investigations’ at the Fall 2016 International Symposium of Microelectronics.

Scientists found plastic coverings started to break down after three hours of exposure to temperatures of 300°C, or about 572°F or more, but memory chips were still readable.

Researchers pointed out that even with the pressures and forces in play during past crashes, temperatures typically only reach those levels for short periods of time.

“Data integrity was maintained even in a plasma discharge,” Cain said. “Basically, if the device doesn’t burn up, there is a reasonable chance of the data being retained in the chip. The only problem is that the connections to the memory chips may be broken, so that the data cannot be read.”

For the second part of the study, researchers addressed the readability issue. The team purposely damaged memory units and then extracted memory chips using acid, lasers, plasma, or mechanical polishing.

Lasers were the most effective extraction method and mechanical extractions was the simplest, but each method still damaged the wire bonds within memory chips and made many unreadable. A specialized metallic ink from a precision printer was used to restore functionality.

The team concluded: “These results expand the investigative scope for aviation accidents, where the data rather than the device are of paramount importance. It is possible to repair the interconnections of flash memory modules, provided the chip is intact.”

More information: EurekAlert!

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