[Blood of Tyrants]

When I worked on commercial aircraft long ago, the ELT’s had a salt water (or urine or any conductive liquid) activated battery and transmit at 121.5 MHz and 243 MHz. But if they went to the bottom of the ocean, the salt water would attenuate the signal to zero.

Submarines have special long wire, towed communications arrays that operate in the VLF band to allow communications underwater.

[itsahoot]

When I worked on commercial aircraft long ago, the ELT’s

I can think of no reason that ELT's on commercial airliners are a waste of money because the data can be transmitted via satellite just as easy as it can be recorded on board.