Communication and Weather Briefing
The flight contacted the Air Route Traffic Control Center (ARTCC) and requested the current weather conditions at Dubuque. The controller advised that the weather was a 500-foot indefinite ceiling, sky obscured, and visibility of one-half mile in fog. The controller further informed the flight that they would be vectored for a back course approach to Runway 13.
Approach Request Changes
After receiving the weather information, the flight crew requested the front course approach to Runway 31. The controller acknowledged and stated that the flight would be vectored for the ILS front course approach to Runway 31. Approximately 40 seconds later, the flight informed the controller that they would instead take the back course approach to Runway 13.
Landing Minima
The landing minima for a straight-in ILS approach to Runway 31 is one-half mile visibility. For a straight-in LOC/DME back course approach to Runway 13, the required visibility is three-quarters of a mile.
Wreckage Location
The wreckage of the aircraft was discovered in a valley approximately three-quarters of a mile short of Runway 13, at an elevation roughly 100 feet below the runway threshold.