Reality is that FOQA systems will never (accurately) determine where A/C touchdown on the runway, as has been mentioned the FOAQ (depending on how clever) system can derive the predicted point, however this is not the touchdown point. Using a algorithm which calculates speed and time you can determine how much distance has been traveled from the Main gear TD to RWY turn off, and providing you have the information, you may be able to determine which exit/taxi way used therefore calculate the TD point. This only works well where you have few exits or even better a pan on a single runway, for example LHR would be a nightmare, where as BHX would be much easier. If your FOQA program has the addition of an animation program, then the above mentioned becomes a little easier and probably more accurate than using geometry.
