What happened
The flight crew was conducting a night arrival at Sidney Municipal Airport when they were cleared for a VOR approach with circling clearance. The published procedure required navigation from the Hancock VOR, maintaining a northerly heading of 354 degrees toward the airport. Instead of following the intended path, the aircraft impacted wooded terrain approximately one mile north of the airfield. The crash site was located near the left downwind leg for Runway 7.
Initial contact with trees occurred at an elevation of about 1,550 feet while the aircraft was paralleling Runway 7/25 on a heading of 255 degrees. The airport elevation was recorded at 1,027 feet, and the minimum descent altitude for the VOR approach was established at 2,280 feet. Weather conditions in the vicinity were reported as having 1,500-foot scattered clouds, 5,500-foot overcast layers, seven miles visibility, and winds from 120 degrees at 5 knots.
The investigation
Examination of the wreckage revealed no evidence of pre-impact mechanical failure or malfunction of any aircraft parts. Propeller blades exhibited signs consistent with rotational damage prior to impact. A toxicology test on the pilot's blood indicated an alcohol concentration of 101 milligrams percent (0.101%). However, because the pilot's body and the wreckage were not discovered until August 15, 1984, investigators determined that the detected alcohol levels resulted from putrefaction rather than intoxication at the time of the accident.
Findings
The aircraft operated below the minimum descent altitude during the approach phase. The pilot failed to maintain visual reference with the airport environment while maneuvering for a circling landing in dark conditions.