Magnetic FDR locator beacon
I know that whenever a plane goes down over water the same question gets asked, 'why is it so hard to find the fdr?'
The two issues are of course the limited range of a transmitted signal under water, and the limited power/duration of a battery powered transmitter.
Given that magnetometers are already used to search for wreckage, and solid state drives replace hard drives, what if a powerful permanent magnet was included in the FDR as a beacon, or even replaced the battery powered transmitter?
The advantages are of course that it won't run out, and even in normal service there are no batteries to worry about. What I don't know is how easy is it to detect a large but steady magnetic field? If magnetometers dragged by a ship can find metallic objects from the distortions in the earth's tiny magnetic field, how would they react to something 100,000 times stronger?