The odds of all 21 parts being found and them knowing same-business-day that the same part of the same supplier isn't on any of their other planes is approximately zero. The odds of even finding all of these 21 occurrences is slim although not zero.
Just logistically there were likely several days or even weeks where they knew there were fraudulent parts in the wild and didn't know whether or not any in-service planes were affected. You're not required to ground your fleet on a hunch, you are allowed to investigate to see if there is actually an issue before bankrupting your legacy airline. I'm not aware of Delta grounding its entire fleet anytime in recent history, so clearly your statement is false.
The odds of all 21 parts being found and them knowing same-business-day that the same part of the same supplier isn't on any of their other planes is approximately zero. The odds of even finding all of these 21 occurrences is slim although not zero.
Just logistically there were likely several days or even weeks where they knew there were fraudulent parts in the wild and didn't know whether or not any in-service planes were affected. You're not required to ground your fleet on a hunch, you are allowed to investigate to see if there is actually an issue before bankrupting your legacy airline. I'm not aware of Delta grounding its entire fleet anytime in recent history, so clearly your statement is false.