Helicopter Underslung Mission
Ashkash, An external load weight indication system can be extremely useful in circumstances, for example, where the personnel preparing a load are 'non-helicopter' and not aware of the the weight limitations or have no means to weigh a load except by 'best guesstimatin' etc. Also, these personnel may not be aware of the flight charactaristics of 'high-density' and 'low-density' external loads. I once witnessed a knock-down, drag-out argument between a pilot and a building contractor because the pilot refused to undersling a sheet of plywood.
Over the years I have come across a couple of systems, if I remember correctly they were manufactured by a) Chadwick Inc, and b) Onboard Weighing Systems Inc.
The only 'minus' of such a system that I can think of is a) it adds weight to the helicopter, but not a lot, in a situation where helicopter minimum weight is very important, and b) the systen will require periodic calibration and maintenance.