A comment on the typical "long" touchdown:
"... overflew the first 4000ft... a normal flare and landing is judged ... by a sense of time ... during the flare, particularly where ground markings are poor / night-time...."
Several runway excursion investigations attempted to explain this float, & the human's misperception of a normal flare.
AAR85-06, pg 40; World DC10/ 23Jan82, off-end BOS 15R:
"...The extended flare resulted in the touchdown about 2,800 feet beyond the displaced threshold.... That the flightcrew believed that the airplane touched down “about 1,500 feet” beyond the displaced threshold may be attributable to the night reduced visibility and the absence of good runway distance measuring references. Even had there been references, the crew would probably have believed that the ... runway remaining at the point of touchdown was adequate for stopping the airplane since it was more than twice that which would be required to stop the airplane on a dry runway. There was no indication that the flightcrew considered aborting the landing at touchdown, and the Board does not believe that the information and cues should have prompted such action...."
TSB/c Occurrence Rpt pg 102, AF A340 off-end 2Aug05 YYZ
"... As they crossed the runway threshold, with the heavy rain, low visibility ... crew members became overwhelmed ... task saturated, making a normal landing difficult. The pilots, who were by this time both focusing primarily outside the aircraft, were not aware that a wind shift was also occurring. While in the flare and the initial float, the pilots did not appreciate how much of the runway was being used up. The tailwind component contributed to ... going above ... and to the overall landing distance required...." ...
Still no information available to confirm AA331/22Dec09's final FLAP configuration during that mishap-landing (never confirmed in either of two rpts so far). Regarding the "normal" final FLAP setting, for TAILWIND approach to a wet rwy, mishap-pilots may have been taught, or became accustom to that "Lower Drag" F30 (rather than F40) configuration; perhaps that became their company's "standard" configuration (?). Recently, the manufacturer may have added to this Final FLAPs confusion with TBC's _Aero_ Qtr_2/2010, story encouraging the "Low Drag Approach" configuration:
"... low-drag approach procedures can save an airline significant amounts of fuel over time ..."
AERO - Conservation Strategies: Descent and Approach