This is how searchers found the wreckage of Air France Flight 447, which went down in 2009 in the Atlantic between Brazil’s northeast coast and western Africa. Underwater search vehicles scanned the mountainous sea floor and sent data back up to experts aboard ships that stayed at sea for a month at a time.
Finally, evidence of possible debris was detected by sonar. Another underwater vehicle with a special high-resolution video camera was sent in to allow scientists to visually inspect the area.
In the case of the Air France jet, it took over $40 million, four lengthy searches and nearly two years before the plane and the black boxes were found.