Helilog, Your memory is letting you down, 350 never suffered from tail rotor hitting boom. The 407 did. AS350 servo issue like Robbo mast bumping- pilot issue but with the 350 lower the lever a little and it is gone, with the robbo low g issue the main rotor head is gone.!! But yes you are correct Robinson is not the only manufacturer with major issues.-- blade ADs etc.