Riveting Ride

My sister returned home from her trip last night. Her plane was supposed to land at 8:30pm. Since I cannot read well this week, I did not check the computer for her itinerary. At 9pm, I called her phone but it was still off. I called again at 9:15 and still no answer. I figured that the plane was delayed. Five minutes later she called me. She said the plane had a 45 minute delay. I asked why. She said that the airline told them that the plane was missing a rivet and they hoped to find a replacement. She thought to herself whether or not they had checked Home Depot yet as they have all sizes. Shortly after that , there was another announcement saying that the rivet was found and being put on. If I was on that plane, I would have needed back up information. First, where was the missing rivet located? Was it from the engine or the coffee machine? Secondly, who replaced it? Was he a mechanic or a guy that just happened to have a wrench? Third, was it a priority rivet or was it the kind that you could have flown without but was nice to have on? I then would have worried for the entire trip, if the rivet was tight enough.