Yeah, the flightaware data shows anything but a ‘normal’ approach when compared to the same flight on previous days. This flight seems to have trouble all the way in. Very unlike the previous days data for the same approach by the same flight.
Though all the interviews say the passengers did not sense anything wrong until the end. But this approach was erratic early on. The flight crew and tower must have known that and worked on it during the approach - or maybe not until it was too late.
I did this landing over 20 times in 2008 usually sitting in the emergency row over the wings on 737s. Long, steady decent with 3 or so flap adjustments on the way in. Hardly ever any noticable speed adjustments once lined up and no noise abatement type adjustments. Just long and steady. The flap motor(s) on a 737 must be right under the seats. It is very noticeable during final in those seats.
To shed the extra altitude would he have had to leave the flaps up or less than normally deployed and cut speed? If so, it seems he may have not gotten them back down and kept cutting speed as well.
At the 600’ point he was basically at what appears to be good speed and position. But he was dropping at 1,300 ft/min at that point and continued to lose speed after that.
I know that on the 737s the flaps crank out slowly and getting them extended takes a few seconds. Going from no flaps to full would seem to take around 30 seconds or more. Not at all instant or quick.
Just some thoughts from a layman.