Fatal Nighttime NDB Approach Accident at Burlington Airport (N111DS)

Accident Overview and Location Details During a nighttime non-directional beacon (NDB) approach to Burlington Airport, a twin-engine aircraft descended below the minimum descent altitude (MDA). The aircraft struck treetops, stalled, and crashed into a wooded area in Winooski, approximately 1.5 miles short of runway 15. The impact occurred in a location characterized by high obstructions. The aircraft was destroyed by a post-crash fire, and all four occupants were killed. The accident occurred under instrument flight rules (IFR) conditions, with the aircraft hitting trees approximately one mile from the outer marker during the approach. The source does not specify the aircraft type, registration, date, or operator. ## Weather and Operational Factors The accident occurred at night with a low ceiling and snow falling. Visibility was below minimums at the time of the accident. The pilot was conducting an NDB approach, a type of instrument approach that relies on a non-directional beacon for navigation. The aircraft descended below the MDA, which is the lowest altitude to which a pilot may descend during an instrument approach without visual reference to the runway. The combination of low visibility, snow, and high obstructions in the approach path contributed to the accident. ## Official Probable Cause The official investigation determined that the probable cause of the accident was improper IFR operation on part of the pilot. The reported factors included the low ceiling, snow falls, high obstructions, visibility below minimums, and the aircraft hitting trees approximately one mile from the outer marker during the NDB approach. The investigation did not identify any mechanical failures or other contributing factors beyond the pilot's operation of the aircraft under IFR conditions.