07/13/2009 -Black box flight recorders, which help investigators determine how a plane crash occurred, are set to get a long-needed upgrade to ensure proper functioning during a crash: back-up batteries.

The New Scientist reports:

Flight recorders are powered by three circuits, each tripping to the next if one cuts out. But recording stops if all power is lost. This happened in 1998, when an MD-11 airliner crashed after a fire burned through its wiring. Investigators found recordings of the flight's final 5 minutes were missing.

The International Civil Aviation Organization then recommended that flight recorders should have back-up batteries by 2004. But technical issues slowed its plan ....

New US registered planes will have battery backed recorders by April 2010, with retrofits on old planes by 2012. Planes registered in Europe will follow suit in 2012.

For a brief history of black box recorders going back to the days of the Wright Brothers, clickhere.

♦ Photo of old-school black box flight recorder byedvvc/Flickr