Within hours of a major airplane crash, media reports inevitably begin to speculate about what happened. The need to know what happened is understandable. After all, with more than 10 million flight departures every year in the United States alone, an undetected flaw in a common aircraft is reason for concern for millions of people. But full answers are usually not readily available. Investigating a crash is a grueling and often thankless task, and recovery experts are often faced with harsh weather conditions, mangled aircraft, and difficult terrain. The human aspect of a tragedy also cannot be ignored. Bodies, or body parts, often litter the ground. Personal articles, from a child's doll to a student's notebook, remind investigators of the halted lives of the victims. Back at the laboratory, researchers piece together plane parts, looking for clues about what happened.

The pressure to come up with quick...