Four injured as helicopter breaks up landing in Brazil   An
investigation is trying to find out why a rescue helicopter
disintegrated shortly after landing in the northern state of
Para in Brazil, injuring four people on board.  Amateur footage
taken by the Para Fire Department showed how the aircraft came
apart while vibrating on the ground.  Officials believe the
helicopter experienced ground resonance, which happens when the
rotor is working while the helicopter is on a level surface.