20211222021919A

Airman was performing a personal flight to give a family member flight in the aircraft. He left his home base in southern Utah to fly to Show Low, AZ. Airman was not on the CTAF frequency and was not aware of the existing traffic. He realized this and changed to the correct frequency. Ground personnel who monitored CTAF stated that the airman apoligized for being on the wrong frequency after being established in the traffic pattern. The same ground personnel noticed that two aircraft were on final to runway 22 and in close proximity to each other. Both aircraft exited the traffic pattern from short final. The accident aircraft was observed making a right turn away from the airport using a medium to speep bank angle. The aircraft was then observed on a verticle nose down attitude. The second aircraft returned to a langing and reported that the first aircraft had crashed and was on fire. Research of the airman discovered that his medical certificate had expired may 2020.