“Passengers should have noticed”.
How many times has this been written and the logic ignored?
Passengers are so used to being late because of traffic or weather holds that they would have paid no attention.
I do wonder about the attendants not asking, because they are usually aware of potential weather or traffic holds well in advance.
So it is odd that no flight attendant asked.
But it could be something as simple as the crew putting the wrong way point into the navigation system and not realizing what they had done until they got to that point, or near it, and found out there was no MSP there.
It would be interesting to know where they reversed or ask to reverse course and what prominent way point was in proximity at that time and whether its ID was anything close to the ID for MSP.
If they used lat. and long., it could have been a simple mistake in the numbers.
It would be helpful if some of the big iron guys would speculate, but I can see the reluctance to say anything that might prejudice the future of these guys.
Losing contact with the center is not at all unusual. What is really unusual and at the heart of the mystery is why, barring an electrical emergency, they had TOTAL radio failure. If they remained on the last frequency expecting to be turned over to the next, center would have a flight in that vicinity call them on their last assigned frequency.
In addition, I would expect that their company would have called them to verify their arrival time.
A very odd incident to say the least.
But, what about the radio? You're right, an odd incident.