No problem paco, I really enjoyed your explaination. Never to old to learn.
I remember a BA landed on a rig deck with a broken starflex causing a massive inbalance condition during rundown. Not quite the classic ground resonance, which can occur with a serviceable helicopter given the right conditions, but the effect was almost the same. Amonst other things, broken tail boom (not due to M/R strike) and lucky it didn't dance over the side.