However, not knowing all the balances at play in this flight regime, my question is to the relative significance of the engine rapidly rising thrust on pylons ahead of the wing causing a pitch up mode vs the tail plane being there or not.
If you refer to the picture in post #655 of this thread, you get a good idea of the overall structure of the A330. Now lop off the tail. Logically a significant change in the CofG occurs in the forward sense - where the CofG would originally have been somewhere centered perhaps slightly aft of the engine centerline, losing the large tail assemble and APU (located at the far extent of the tail cone) would result in a large change forward. Hence the result of engine thrust would logically be pitch down. And all this ignores the lift generated by the horizontal stabilizers.
- GY