underwater beacons on CVRs and DFDRs
As I am reading the news on MH370's search in the South Indian Ocean, I came to realize that these underwater beacons look like really cheap and outdated devices. Starting with the beeping for only 30 days. As with AF447, 30 days proved to be a ridiculous short time a find anything in the high seas. Surely the cost and weight of a 6 month-life battery is by no means a financial or technical burden on an airline; look at bulletproof cockpit doors for a comparison.
I don't know the very technical data of the underwater pinger, but to quote a line in some online news article:
"The range of the pinger is limited because it uses a relatively high frequency of 37.5 KHz. In water, high-frequency sounds travel shorter distances, meaning the pinger signals can travel only 2,000-3,000 metres."
Damn! This is where we're at, in the 21st century?! For millions of years the ocean floors had depths in excess of 6000 meters in places, what do we expect from a plane going down at sea? To float for 3 months?
Is there today any pinger that does a better job? Like a lower frequency to get a better range underwater, or a CVR/FDR mounted with a battery lasting a year?
What I am talking about here are not technological breakthroughs, but merely upgrades to existing equipment, as it is obvious in this day and age, that we can't find an aircraft in the time available from the pingers batteries to give off their position, let alone the depth at which they could be transmitting from, incompatible with surface detection... time for a change?