The FDR & CVR each (or two dual-function units) both have pingers. That's what is a little confusing to me. The things are designed to begin operating when they get wet, operate for at least 30 days, and are designed to be found acoustically. The gulf there is relatively shallow and flat, so I would assume the detection would be relatively easy compared to AF447 hidden in a bunch of underwater mountains.
The searched for the pingers in the first 30 days right where they eventually found the debris, but did not detect them for some reason.
http://www.flightglobal.com/news/ar...acoustic-sweep-missed-af447-recorders-356286/