I'm not a pilot, just a bit of frequent flyer and moderate aviation enthusiast. I sometimes get on Flightaware and check on the flights I frequent and see the path that was taken and flight time. I noticed today on the track log that a ORD-GSO flight airspeed dropped below 100mph while lining up for the approach. I had never seen this before and was curious to how often this happens? Isn't this dangerously slow even for the short time?