Originally Posted by MrSnuggles
Do anyone here know if that animation of the trajectory after (whatever happened) is based on scientific calculations or if it is just a conjecture based on eyewitnesses statements?
This is what Wikipedia says about your question :
"Only the FAA radar facility in North Truro, Massachusetts, using specialized processing software from the United States Air Force 84th Radar Evaluation Squadron, was capable of estimating the altitude of TWA 800 after it lost power due to the CWT explosion.[99] However, because of accuracy limitations, this radar data could not be used to determine whether the aircraft climbed after the nose separated.[99] Instead, the NTSB conducted a series of computer simulations to examine the flightpath of the main portion of the fuselage.[100] Hundreds of simulations were run using various combinations of possible times the nose of TWA 800 separated (the exact time was unknown), different models of the behavior of the crippled aircraft (the aerodynamic properties of the aircraft without its nose could only be estimated), and longitudinal radar data (the recorded radar tracks of the east/west position of TWA 800 from various sites differed).[101] These simulations indicated that after the loss of the forward fuselage the remainder of the aircraft continued on in crippled flight, then pitched up while rolling to the left (north),[98] climbing to a maximum altitude between 15,537 feet (4,736 m) and 16,678 feet (5,083 m)[102] from its last recorded altitude, 13,760 feet (4,190 m).[21]"
P.S. A quick sum shows that an object travelling at 400 kts can gain about 7000 ft of height ballistically.