Originally Posted by
Capt Kremin
An objective analysis of the the FR24 supplied ADSB data raises many questions.
Interesting graphic.
The altitude spike where the aircraft dips below the runway surface(!) accompanied by a single, instantaneous 2000+ fpm ROC value is clearly an artifact (unless Newton got it all wrong), probably coinciding with rotation.
There is a similar, spurious altitude spike towards the RH edge of the plot, which you have wisely ignored - that one is easier to account for because a distance-vs-time plot shows the aircraft flying backwards at that point (i.e. it's a timestamp anomaly rather than bad ADS-B data).