[Non-Sequitur]

I believe 737’s, 747’s & L1011’s have been grounded briefly for rudder control & engine problems.

I've heard that individual airlines may have grounded their aircraft following an incident, but certainly in the case of the 747 and L-1011 I've never heard of a worldwide grounding.

[UCANSEE2]

Hmmmmmm... the Concorde.