kuobin,
As FOQA becomes more widespread, naturally more pilots will be interested in the details. And I do not wish to diminish your commendable curiousity for anything technical in aviation.
However, the best way for a line pilot to approach FOQA is to simply know that it is there, and avoid making any decisions or developing any techniques based on your knowledge of FOQA events and alert thresholds.
To do so would be the equivalent of assessing your car driving skills by looking only in your rear vision mirror and examining where you have been, and noting the location and severity of dents when you park.
Far better to relate any FOQA event and threshold to FCOM recommended Procedures and Techniques for your type.
And ensure that your pilot representative body has adequate arrangements covering the use and confidentiality of QAR data.
Having said that, I should descend from my pulpit!
Remember that Power + Attitude = Performance.
In the range of 1000' to 100' on final approach, you should be stabilised in the approach configuration. You are not yet in the landing flare.
You say your type has a typical pitch attitude of 5 deg ANU (aircraft nose up) in landing config when on glideslope.
I am guessing that your Vapp is in the vicinity of 120kt-140kt. Giving a target descent rate of 600-700fpm to maintain a 3 degree path to the touchdown point.
At 120KIAS a pitch attitude change of 1 degree roughly equates to a 200'/min change in RoD or RoC.
Therefore a 2 degree ANU change would reduce your rate of descent by approximately 400fpm and a 4 degree ANU change would reduce your rate of descent by approximately 800fpm.
Assuming that 120KIAS is maintained by you or your autothrottles.
Therefore FOQA wants to know why you have selected a pitch attitude that would normally result in only a 200-300fpm descent (level 1) or level flight to +200fpm climb when the target is a 600-700fpm rate of descent.
The attitude is not one that would normally provide a stabilised approach.
Does that assist?