It will make sense at this stage to make an educated guess regarding the aircraft's crash position using Inmarsat data and send in a few ROVs to the ocean floor. This preoccupation with locating debris as marker for crash location in the roaring 40s is looking less and less fruitful.
Tedious as it may be, locating the wreckage through floating debris then backtracking to the crash site is still going to be the quickest way. Anything else is just a guess.
All Inmarsat data can do is take us down 90% of the track south. That final 10% which can't be predicted by hard data represents a hell of a lot of ocean.
