"Stealth Pilot" wrote in message
...
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.

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

on most light private aircraft just how critical is the weight anyway?
do you think it might be a solution in search of a problem?
Stealth Pilot

Thanks for remindig me, because those are two of the three reasons why such
a system can never give an accurate weight and balance.

The thrid, which is closely related, is hysteresis in the system--especially
if the brakes are applied and/or hydraulic and/or pneumatic pressure is
measured.

As an asside--I was amazed to witness how little air movement it takes to
totally disrupt the weighing of a light aircraft. You really couldn't feel
any breeze, but we still had to close the hangar doors to get usefull
results!

Peter