Another great post Sav, excellent explanation.
And heres what happened to this Alouette
"In December 2005, an Aerospatiale Alouette III landing at EscalanteNational Monument in Utah suffered ground resonance that tore the helicopter apart in four seconds. All aboard survived "
Nice image of EI-ATO, taken in Donegal in 1970 I think. Prime Ferranti period.
Cheers, S