Incident
The airplane collided with trees while attempting to land in instrument flight rules (IFR) conditions of near zero visibility in fog.
Communication
While en route to the destination airport on an IFR clearance, the TRACON controller observed the airplane's transponder discrete code change to 7600, used by flight crews to indicate a communications failure. The TRACON controller determined that the pilot could hear them, but they could not hear his transmissions. Because of the requirement for full communications in controlled, Class B airspace, they suggested the pilot contact a nearby airport outside of the Class B airspace on the frequency they provided. The pilot contacted the suggested ATCT while 12 miles west of that airport, and the controller could barely hear the pilot's transmissions. The pilot advised the tower to cancel his IFR flight plan and he would proceed visual flight rules (VFR) back to his departure airport without VFR flight following. This was the last communication from the pilot.
Approach Attempts
Witnesses heard the pilot make two approach attempts to land at original departure airport but they could not see the airplane because the airport had become zero visibility and zero ceiling in fog about 20 minutes prior to the airplane's arrival.