@deSitter
No question it's the APU, obvious really. The airplane is torn all to hell. I don't see how this is possible without a high speed impact
.
Don't underestimate hydraulic damage, particularly if the object is impacting in excess of 70M/s. Take a look at the bulkhead damage for US Airways Flight 1549.
http://www.ntsb.gov/Dockets/Aviation...026/418716.pdf