@NSEU
Good luck getting the black boxes to float!
Armour plated for crash resistance, for their size, they would have to be the heaviest boxes on the aircraft. You'd have to find a crash resistant/fire proof floatation device of considerable size.
Indeed... not to mention this little comment right at the end of the article.
"It would also help to indicate the
exact point of impact at the time of the crash and to find the wreckage."
Airbus to get ejectable black boxes