If 70% of aircraft crashes are caused by high level sabotage (or whatever number Q said) then this implies several possibilities about the NTSB:

1) they're complicit in the sabotage and thus part of the swamp helping to cover it up

2) they're incompetent at their jobs and can't even recognize sabotage

Or 3) the sabotage is very subtle and hard to detect

Knowing how well the NTSB operates and the CSI-level abilities they have, I'm inclined to suspect they are not part of the conspiracy and the saboteurs are quite sophisticated indeed.