Highly unbelievably that 1 kg of TNT can cause such thing in less then 1 sec (and in 1 sec frame there will be at least dozen readouts at FDR).
Kulverstukas,
I think you could stop the FDR with 10ozs if you put it in the right place, i.e next to the power supply. The fact that the FDR reportedly stopped after 1 second would suggest to me that the power supply was immediately interupted by the initial explosion. What happened after that was chain of events, leading to the liberation of the tail section etc. etc.