Flightradar 24 (in)accuracy
Whilst for the heavier metal (with full GPS location via ADS-B out) flightradar data is very accurate (excluding loss of signal and the estimation which is then involved), smaller GA aircraft data is an approximation at best.
I would urge caution before making statements such as w,xyz fpm descent rate on the 152 prior to impact.
In a simple form: How flightradar generally works for GA aircraft is it requires several ground stations to receive the transponder signal from an aircraft. It then calculates based on the known locations of the ground stations and the differences in the time received between the transponder signal at each of these locations. Over time it can estimate the altitude, speed and direction of the aircraft. For a really basic example of this; turn off your GPS, wifi and bluetooth on your phone and open google maps and look at the margin of error circle around your position.
A lot of the accuracy of this system depends how accurately a user records the positon of their flightradar receiver (typically done manually) and how many different receivers receive each transponder transmission.
I believe (but I don't know for sure about this) - that a lot of "smoothing" or "averaging" is applied to the data received by flightradar to give a sensible relatively consistent reading.
I would expect that in a scenario such as this (sudden loss of signal or wildly varying data for want of a better way of putting it), that the recently reported data by flightradar would be suspect at best. I've looked at the raw data reported by flightradar (CSV format - maybe worth a look for the curious) and I believe there is a reasonable amount of inaccuracy there. I do not know how much.
Note: I do not know the cause of this accident - Nor will I be making any assumptions - I would however urge caution about treating heavily filtered data as 100% accurate.