Why Do Airlines Keep ‘Black Box’ Flight Data Trapped on Planes?

To solve the mystery of what happened to Malaysia Airlines (MAS:MK) Flight MH370, investigators need the airplane’s data and voice recorders. In an airplane tragedy, however, the information stored in the so-called black box inevitably ends up inside a wreck. This seems like a terrible place to keep the clue you need to find most.

As investigators scour the Gulf of Thailand and waters as far north as Hong Kong for debris from the Boeing (BA) 777-200 that vanished en route to Beijing on Saturday, there’s almost no indication yet of what doomed the flight and the 239 passengers on board. So far, at least, no wreckage or jet fuel has been found. Without recovering the black box, there’s little way to know what caused a plane cruising at 35,000 feet to disappear from radar.

Why not transmit this flight data off the plane so it’s accessible almost instantly? Airlines, after all, track each of their flights everywhere in the world and can advise crews on course adjustments, security alerts, quick weather changes, and a host of other situations. Passengers are routinely offered in-air Wi-Fi and live television these days. So why keep vital data trapped on the plane?

The answer is mostly about one issue: cost. Sending all the data from each flight in real time via satellite would be enormously expensive. A 2002 study by L-3 Aviation Recorders (LLL) and a satellite provider found that a U.S. airline flying a global network would need to spend $300 million per year to transmit all its flight data, even assuming a 50 percent reduction in future satellite transmission costs. And that’s just a single airline. Commercial airline disasters, meanwhile, are becoming even more uncommon as technology and techniques improve—in part thanks to lessons from past crashes—so there’s little incentive for investing heavily in real-time data.

Businessweek last explored this question in July 2009 as French and Brazilian authorities searched a wide section of the Atlantic Ocean for a missing Air France (AF:FP) flight. The data recorders aboard the Airbus (AIR:FP) A330 remained missing for almost two years, some 2 miles beneath the surface, before searchers finally recovered them.

If the Malaysia Airlines flight did go down at sea, as searchers believe, waters in the suspected crash area are much shallower than in the region of the Atlantic where the French jet went down. In both cases, meanwhile, the flight data and cockpit voice recorders were made by Honeywell (HON) Aerospace. Despite the conventional term “black box,” the Honeywell recorders and most others in use are actually bright orange in color.

Of course, there remains the possibility that a powerful enough calamity could have obliterated the data boxes on the Malaysia flight, leaving investigators without their best hope for discovering what went wrong. No data recorders were ever recovered from the two Boeing airplanes that crashed into the World Trade Center.

Source: http://www.businessweek.com/articles/2014-03-10/malaysia-air-crash-why-do-airlines-keep-black-box-flight-data-trapped-on-planes