People rely on electronic devices extensively and would always have gadgets among their personal effects. For this reason, officials from the National Transportation Safety Board rely on digital clues in flash memories of electronic devices in the event of an accident.
A research team from Binghamton University - State University of New York has figured out how much damage memory units could take before becoming unreadable. New repair techniques to extract data from damaged units could also aid in preventing future tragedies.
"The biggest surprise was how much punishment these devices can take before ceasing to function," explained Steve Cain, a senior research support specialist in the Integrated Electronics Engineering Center at Binghamton University and the manager of the project. "As part of their post-crash investigations, the National Transportation Safety Board 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 study, titled "Fire Damage and Repair Techniques for Flash Memory Modules: Implication for Post-Crash Investigations", was conducted by testing plastic coverings, The researchers found that these begins to break down after three hours of exposure to temperatures of 300 degrees Celsius. The memory chips, however, were still readable.
Given the pressures and forces in play during past crashes, the temperatures are similar to those tested by the research team. This doesn't necessarily guarantee an intact memory chip. "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."
The research team also intentionally damaged the memory chips using acid, lasers, plasma, and mechanical polishing to test readability. Lasers were the most effective extraction method but each method damaged the wire bonds in the memory chips to the point of unreadability. A specialized metallic ink from a precision printer was then used to restore functionality.
"These results expand the investigative scope for aviation accidents, where the data rather than the device is of paramount importance," the team concluded. "It is possible to repair the interconnections of flash memory modules, provided the chip is intact."