Energy of unused fuel at 80% remaining = 0.8*35000* 42,800,000 = 1,218,077,275,484 J
Energy of a ton of TNT explosive = 4,184,000,000 Joules.
TNT equivalent of plane was a Ton of TNT.
TNT equivalent of remaining fuel was 290 Tons of TNT
An Exocet missle, used to turn a ship in the Falkland islands war into a floating slag has a warhead equivalent of 1/6th a Ton TNT. So the plane by itself slammed into the building like 6 Exocets.
For a massive ordinance penatrator bomb (bunker buster) weighs 13,600 KG ( 1/7th of the plane weight) it’s warhead is 2.7 tonnes, 1/100th of the energy in the plane’s fuel.