[JohnG45]

I can't remember a single time the FAA ordered a airplane grounded following a crash due to unknown cause.

But they said they had a KNOWN cause - faulty wiring in the center fuel tank.

[DoodleDawg]

But they said they had a KNOWN cause - faulty wiring in the center fuel tank.

Then they send out inspection and modification orders. They have never ordered a mass grounding, other than the 787, so there is no reason why they should have for the 747 post TWA 800.