Originally Posted by
iskyfly
Would somebody be kind enough to recap ELT and CVR/FDR ULB ranges underwater and if working what type of equipment would be able detect them?
Thank you
ELTs transmit on a satellite and some on aviation emergency frequencies and can be 'seen' by satellites almost anywhere on the Earth's surface. However, underwater their range is zero.
The CVR and DFDR underwater locator beacons have a range of ~2 - 3km underwater and are at a high frequency that almost all SONAR systems will not detect, their batteries are pretty wimpy too and may last 30 days 40 if extremely lucky. These design features seem to be at the behest of the airline beancounters.
To find the ULBs it is usually necessary to get within 2 km with a towed special purpose SONAR array, one is being transported from the US to the search area. However, the Indian Ocean in that area can be more than 3km deep..... Had the beancounters allowed a couple of hundred dollars more per aircraft then the ULBs could be lower frequency higher powered and a few hundred kilometers range and detectable by almost any ship with SONAR.
I would put the beancounters on deck on the SAR ships in the roaring 40's give them some binoculars and keep them at it till the wreckage was found.
