Don't the practical realities of SAR add to the need for more data to be available? How difficult would it be to have a SATCOM system which was armed climbing through 20k and which automatically burped out position data on descending through 2k then every x seconds until goodbye and closing the channel at 200ft say? You could regain some weight and cost by junking the ELTs which appear to be occupying space normally reserved for chocolate teapots!