Main data inputs are:
Recorded a/c weight
Speed over platform correction. (0-5 Knts)
Head wind speed.
Gust factor.
Model wind correction.
Aircraft registraton capture.
Aircraft performance data (Limitations)
Aircraft CL data from manufacturer (If available)
The mathematics are for the software engineer and are proprietary.
As for the advertising comment.
Part of the problem of introducing an external weight & balance system to aviation is the perception (False) that the present system is "safe."
Until it is recognised that the problem of loading errors is real and constituets a "significant" threat to safety the argument can get mired in defensive rhetoric.
One of the false arguments currently in vogue amongst many regulators is that the problem is restricted to light RPT aircraft.
The logic for this is the simplistic analytical view shown as follows.
A comparison of various aircraft types indicates that the ratio of passenger weight to overall aircraft weight is inversely proportional to the size of the aircraft. For example, in a Boeing 747, the passenger weight represents approximately 9 per cent of the aircraft's weight (450 passengers at 188 pounds, aircraft of 875 000 pounds) whereas the passenger weight in a Cessna Caravan can represent approximately 22 per cent (10 passengers at 188 pounds, aircraft of 8550 pounds). For aircraft under 12 500 pounds, there can be significant deviations from the published standard passenger weights due to the small sample size (nine passengers or fewer). This deviation error is further amplified in small aircraft due to the higher percentage of total aircraft weight that the passengers represent. If a small aircraft is being loaded to maximum gross weight, this discrepancy in passenger weight could result in an overweight condition that adversely affects the safety of flight. For example, stall speeds increase with increased aircraft weight; if the pilot is unaware of this change to aircraft performance, the reference speeds used for critical phases of flight will be incorrect.
The real world however is not this simplistic.
In my threat and error model I have considered a range of systemic threats as well as a a wide range of analytical threats.
When an error occurs it is the eroor management or mismangement that determines the risk.
The main problem as acknowledged by leaders in the accident investigation field is that large RPT aircraft do not have any other weight and balance evidence than the load sheet and expert witness testimony after the crash.
Reconstruction, the convential method for accident investigation is often impossible or impractical with large RPT aircraft.
I don't want to get banned from this forum for giving out a commercial web site but if you are interested in the threat & error model development please email me.
Once more in the industry are aware of the real problem and the need for a solution (Hard data, education and publicity) then the discussion should be how do we implement change.
Chok dee.