Indonesian Air Force officers examine a map of the Malacca Strait during a briefing following a search operation for the missing Malaysia Airlines Boeing 777, at Suwondo air base in North Sumatra, Indonesia, on Wednesday. AP2014

Days after a Malaysian airliner with 239 people aboard went missing en route to Beijing, searchers are still struggling to find any confirmed sign of the plane. Authorities have acknowledged that they didn't even know what direction it was heading when it disappeared.

As frustrations mount over the failures of the latest technology in the hunt for Malaysia Airlines Flight MH370, some scientists say an 18th-century mathematical equation – used in a previous search for an Air France jetliner's black box recorder – could help pinpoint the location of the Malaysian plane.

In 2009, Air France Flight 447 en route to Paris from Rio de Janeiro vanished over the Atlantic Ocean, triggering the most expensive and exhaustive search effort ever conducted for a plane. After two years, officials could only narrow the location of the plane's black box down to an area the size of Switzerland.

But Flight 447’s black box was found in just five days after authorities contacted scientific consultants who applied a centuries-old equation called Bayes’ Theorem.

“It’s a very short, simple equation that says you can start out with hypothesis about something — and it doesn’t matter how good the hypothesis is,” said Sharon Bertsch McGrayne, author of “The Theory That Would Not Die: How Bayes' Rule Cracked the Enigma Code, Hunted Down Russian Submarines, and Emerged Triumphant from Two Centuries of Controversy.”

That’s because the hypothesis can keep changing and improve, and still be used with the theorem, McGrayne told Al Jazeera.

“You are committed to modify that hypothesis every time a new piece of information arises,” McGrayne said.

Bayes’ Theorem, which is also used in Google’s driverless cars and predictions in stock markets, is based on probability. Because the theorem starts with a hypothesis – something McGrayne said “can be very subjective” – it had been seen as controversial until the 1960s. But because it forces researchers to change their hypothesis with each new piece of information, the probability becomes more accurate.

The theorem was used in World War II to locate German U-boats and the lost nuclear submarine U.S.S. Scorpion. It was also used during the Cold War to spot Soviet submarines.