Airbus is nearly ready to equip airliners with recorders that eject, so that they float to the ocean's
Black boxes are equipped with an emergency locator transmitter that would be easier to detect if floating on the water's surface.
Questions about deployable black boxes arose after Malaysia Airlines Flight 370 disappeared in March 2014 (although I blogged about this very issue back in June 2009, after Air France 447 went down over the Atlantic).
Airbus plans to put deployable recorders in its A350 and A380 airliners, which are designed for long-haul flights over ocean. But Boeing says there'll statistically be only one accident every 10 years where a commercial jet crashes into the ocean and can't be found for more than a year, whereas 5-6 accidental ejections are likely each year.
Surely if the issue is whether or not a black box may self-eject (and that's a highly speculative may, given that these have not yet been introduced), the answer is to have a duplicate box installed in the usual place. If one is lost, the other continues to operate!
...or, as I said 5yrs ago, military-grade nano-burst technology (readily available now) that negates the need for a 'black box'!
For every problem, there's a solution...and the travelling public's peace-of-mind requires a solution.