henra:
That was admittedly a bit harsh, but the idea that NTSB was seriously not clear about investigating this drove me mad. Every small Cessna that dings a wing is investigated and here we have case of a potentially very close call situation for a fully laden Heavy and they are not sure if they need to investigate.
The NTSB delegates non-fatal GA accident investigation to the FAA. Fatal GA accidents are not delegated but some of the field investigations these days are sloppy.
Incidents are strictly optional.