Background
At 2015, a flight was in contact with Air Route Traffic Control Center (ARTCC) and requested the weather at Dubuque. The controller advised that Dubuque reported a 500-foot indefinite ceiling, sky obscured, and visibility of 1/2 mile in fog. The flight was initially vectored for a back course approach to runway 13.
Sequence of Events
The flight then requested a front course approach to runway 31, and the controller agreed to vector them for the ILS front course approach to runway 31. Approximately 40 seconds later, the flight informed the controller that it would instead conduct the back course approach to runway 13.
The published landing minima for a straight-in ILS approach to runway 31 was 1/2 mile visibility, while the straight-in LOC/DME back course approach to runway 13 required 3/4 mile visibility.
Wreckage Discovery
The aircraft's wreckage was located in a valley about 3/4 mile short of the threshold of runway 13 and approximately 100 feet below the runway elevation. The wreckage was found about two days after the accident. Both occupants were killed.
Investigation Findings
Official findings determined that the accident involved an in-flight collision with terrain during the approach phase from the final approach fix to the threshold under instrument flight rules (IFR). Key findings included: dark night conditions, fog, low ceiling, and weather below approach/landing minimums. The pilot in command was found to have improperly executed IFR procedures and descended below the minimum descent altitude.