G/VS...
Hi.
I have generally used the VS at 1 sec before touchdown for the most reliable assessment of a hard landing.
The g recorded by the QAR/AIMS can give distorted information, as it may be affected by pitch rate & cg location. The gz accelerometer is normally located at a natural node of the longitudinal axis, and is not often near the average cg location.
Algorithms to filter pitch rate out of the vertical load are not that great...
The sink rate immediately before touchdown has few confounding factors, and normally a value around 550FPM at TD-1sec will result in about 1.7g.
good luck with it, the manufacturers normally don't recommend the use of the QAR data to assess a hard landing, it is more often the case that the pilots opinion is the determinant.
FDR