The Fairfax County 911 Center in Virginia takes calls during Hurricane Sandy in 2012. It was relatively easy to locate callers when most people used landlines. But most 911 calls now come from cellphones, which can pinpoint a callers' location only within 100 to 300 meters. Greg E. Mathieson Sr./Mai/Landov hide caption

itoggle caption Greg E. Mathieson Sr./Mai/Landov

In Beijing, anxious relatives continue to wait for word about the fate of Malaysia Airlines Flight 370. The Beijing-bound jet disappeared on Saturday. Mark Ralston /AFP/Getty Images hide caption

itoggle caption Mark Ralston /AFP/Getty Images

A passenger checks his cellphone while boarding a flight in Boston. The Federal Communications Commission is proposing new rules to allow using cellphones for data and voice calls during airline flights. Matt Slocum/AP hide caption

itoggle caption Matt Slocum/AP

The new head of the Federal Communications Commission says his agency is reviewing restrictions on in-flight cellphone use. Here, a passenger looks at her cellphone before a flight last month. Matt Slocum/AP hide caption

itoggle caption Matt Slocum/AP

The new head of the Federal Communications Commission proposes allowing airline passengers to make phone calls during flights. Here, a passenger looks at her cellphone before a flight last month. Matt Slocum/AP hide caption

itoggle caption Matt Slocum/AP

Cell towers are constantly tracking the location of mobile phones. And that data, federal courts have ruled, is not constitutionally protected. Steve Greer/iStockphoto.com hide caption

itoggle caption Steve Greer/iStockphoto.com

A row of beer cans in Australia, where a man's beer fridge has been blamed for playing havoc with the cellphone network in several neighborhoods. Torsten Blackwood/AFP/Getty Images hide caption

itoggle caption Torsten Blackwood/AFP/Getty Images