Since we're talking electronic sensors...

Stealth Pilot wrote:
On 14 May 2009 10:37:08 GMT, Michael
wrote:
"The issue is that you need to certify the thing, or you can't use it
for any flight crew annunciations. So, to certify it, you need to be
able to guarantee performance. And, if you can't certify it, you can't
take any credit for it being there. Still a potential safety
improvement, but not nearly as cost effective as beating on the flight
crew and dispatches to make sure they actually put in the real
weight."

I've heard a discussion of this and the point made was that the wings
are still flying while parked on the ground. in still air the system
would work but with a breeze, or worse in gusts, the system may never
sense the actual aircraft weight.

So the system could incorporate signals from strain gauges(gages?)
attached to the wings and rudder. Then those forces could be included in
the computation. A nice side benefit of such instrumentation is that one
can view and have recorded a history of the forces on the aircraft during
flights. All your landings where you had a nice squeaker (or dropped it
in) precisely quantified and forever preserved, if you so desire! :-)

the other problem was calibrating the weighing (certifying the thing)
and finding really horizontal ground all the time.

Could also incorporate a signal from a gravity attitude sensor (e.g.
damped plumb bob). Can't think of any useful side benefit to that extra
sensor, though.

on most light private aircraft just how critical is the weight anyway?

C.G. is the useful thing on all size aircraft.

do you think it might be a solution in search of a problem?

Some homebuilders are putting $10k++ instrument panels in their
experimentals that are often expensive solutions in seach of problems, so
I don't see any problem at all in experimental minded builders playing
around in such an underlooked area. Compared to experimenting with things
like engines, attaching sensors is a relatively benign area to experiment
in. (Not entirely benign of course - e.g. one could badly place sensor
wire runs that interfere with controls.)