How did a single teenage girl survive the Yemenia crash?

Rescue efforts are continuing along with the search for the flight-data recorders from the Yemenia Airlines plane that crashed early Tuesday morning on its way from the capital Sanaa to the Comoros Islands.

French officials now say earlier reports that a "pinger" signal from the black boxes was located were inaccurate. The signal that was detected came from a distress beacon.

In the meantime, the recovery of a sole survivor – reported to be 12-year-old Baya Bakari – from Tuesday's early-morning crash has raised the perplexing question of how one person could live through a catastrophic accident in which everyone else perishes.

The answers are not simple, aviation analysts say. They involve the complex physical dynamics in each individual accident. Since 1970, there have been 12 cases in which there has been only one survivor, according to a study by Airsafe.com. Two-thirds of them were either flight crew members or children.

"This might be the 13th case," says Todd Curtis, an aviation expert and founder of Airsafe.com, who conducted the study. "It becomes a question of what were the specific dynamics in that specific area that allowed that person to survive. There are so few data points and no real in-depth research about this kind of crash, so it's really hard to say exactly why."

But there are many factors that could contribute to the survival of only one person – from to where that person was sitting at the time of the crash, to whether they were facing forward or backward, to whether they are big or small. One British researcher believes the reason so many children survive is because they're shorter than most adults so their heads don't rise above the back of the seat. That allows the seat to act as a kind of safety cocoon in an accident.

Dr. Curtis of Airsafe.com says that is one possibility.

The type of seat in which a person is sitting

and where it's located may also help explain why a disproportionate number of flight crew survive, he says. For instance, seats in the cockpit are constructed to be far stronger than a regular passenger seat.

"Some crew seats are also in a different position. Typically, the jump seats [used by flight attendants] are against the bulkhead and the flight attendant might actually be sitting with his or her back to the front of the airplane," he says. "So in a crash when everyone else is being thrown forward, they're basically being pinned against the back wall, and that might save them."

Another key factor is how fast rescuers get to a scene. In a 2006 ComAir crash in Lexington, Ky., the first officer was the sole survivor. The plane crashed on takeoff and caught fire. The first officer was trapped in the plane but survived primarily because rescuers arrived at the scene very quickly and were able to extract him.

In the case of Tuesday's Yemeni crash, the young teen who survived reportedly "heard people speaking around her," according to French news reports. That's an indication that others may have initially survived, but perished in the cold water before rescuers could arrive. The young teen reportedly clung to a piece of the wreckage for more than 12 hours before she was rescued.