GB
If AF447 had been sending its position via SATCOM every minute instead of the 10 min interval initiated by AF Operations/Maintenance, the search area would have been reduced to a maximum of 8NM radius. That's assuming it crashed in the 59th second, which gives an area of 201 square NM (690km^2). We do know that it was still airborne 4 minutes later, and the BEA are using 0215z as their crash time. This represents the 8 x 5 = 40NM radius they are ostensibly confining their search to, i.e 5026 sq. nautical miles (17,240km^2).
This boils down to one simple fact, i.e. the search area increases by the square of the time between position reports.
Just phoning home at smaller intervals increases the SATCOM costs proportionately, but reduces a search area by the square root of the changed interval. The costs of one versus the other are too large to even contemplate.
In meantime, implementing the above is the cheapest thing that AF or any other carrier operating Oceanic routes outside of SSR coverage could do right now.
Any other changes, e.g. GELB (GEPIRB) and ULB pinger frequency, are going to take time and cost a lot more money.
mm43