What happened
During a night arrival in weather characterized by drizzle and fog, the pilot was performing an ILS approach to runway 1L. During the descent, the pilot reported encountering moderate rime ice. Radar tracking indicated that the aircraft maintained its course along the localizer until it reached the vicinity of the middle marker, at which point it drifted approximately 20 degrees to the left. The aircraft subsequently struck the ground roughly 300 feet left of the runway threshold and 300 feet short of the runway.
Witnesses at the scene observed that the aircraft appeared to reduce its airspeed and level off its descent shortly before entering a steep descent and a spin. There were 0 fatalities reported in the provided text, though the impact was a ground collision.
Findings
An investigation of the wreckage showed no evidence of malfunctions regarding the powerplant, control systems, or the airframe prior to the impact. However, ice accumulation was noted on the wings, specifically a 1/4 inch layer on the leading edge and a 1/2 inch ridge of ice located approximately 3 inches behind the deicing boots. Additionally, investigators discovered that the heating systems for the windshield and cockpit were set to the 'off' position.
Discrepancies were also noted in the pilot's documentation. While company records indicated the pilot had completed a 14 CFR Part 135 checkride on May 20, 1994, signed by the chief pilot, other available information suggested the chief pilot could not have conducted the evaluation on that specific date.