An old-school cockpit voice recorder and flight data recorder (right) on display from United Airlines flight 232, which crashed in 1989.

Renato Rotolo/AFP Photo/Getty Images

The 2014 disappearance of Malaysia Airlines Flight 370 revived a recurring debate over whether airplane black boxes were keeping pace with the times. In our big-data-and-cloud-storage era, when satellites and cell towers pump everything from sports to stock prices to our smartphones, why do we still lock away critical data on a box that can go down with the plane?

It wasn't a new argument. Similar questions cropped up during attempts to locate the black box from Air France Flight 447, which crashed into the Atlantic Ocean in 2009, killing 228 people. Searchers spent two years hunting down that device, which lay so deep -- 12,800 feet (3,900 meters) -- that rescuing it required a special robot sub. Had not Honeywell's black box surpassed its required specs, the device would have succumbed to water and pressure long before. MH370 is believed to lie thousands of feet deeper still [sources: Adler; Paur; Washington Post].

But the Malaysia Airlines flight raised another potential weakness, as it soon became clear that data vital to understanding the flight's fate had likely disappeared long before the plane. To see why, let's look at how black boxes work [source: Adler].

Black boxes contain two recorders. The cockpit voice recorder (CVR) stores sound from the crew's microphones and earphones and from area recorders mounted on the cockpit's roof. Beyond taping crew or tower exchanges, it captures ambient noise or alarms [sources: Adler; Demerjian; Kavi; National Geographic].

The flight data recorder (FDR) archives snapshots of aircraft performance based on data fed to it from all over the plane. Every few seconds, a flight data acquisition unit info-dumps at least 88 different factors -- heading, fuel, altitude, airspeed, vertical accelerations, throttle and flight-control positions, wing flap movements, that sort of thing -- to the FDR. Some commercial airlines track hundreds or even thousands of data points. Just what info the recorder gathers depends on whether the plane is taking off, landing or cruising, and the update rate can kick into higher gear during a crisis [sources: Adler; Demerjian; Kavi; National Geographic].

But while the data recorder operates on a 25-hour loop, the voice recorder overwrites itself every two hours. In a case like MH370, that would wipe out the key moments of the flight -- specifically, the cockpit chatter that took place during the plane's course change [sources: Millward; Wald].

Just because a system has a few flaws doesn't mean you chuck it for something new. All systems have failure points; the art of engineering, and of good policy, lies in balancing them against more useful features. Does the black box need a 21st-century update? And, if so, is cloud storage practical, affordable, reliable and secure enough to supplement or replace the status quo?