What happened
During an instrument flight rules (IFR) approach following a Boeing 727, the aircraft registered N81589 experienced a sudden leftward deviation of nearly 90 degrees approximately 2.5 miles from the runway. At the moment this deviation occurred, the preceding 727 was at an altitude of 850 feet on the ILS glide slope, maintaining a separation of 4.7 miles from the following aircraft. Shortly after the course deviation, the pilot reported encountering severe turbulence and attempted to climb.
The aircraft subsequently flew through treetops over rising terrain for roughly two city blocks. During this descent, the plane struck power lines and a utility pole before ultimately crashing into a tree. The flight occurred under conditions of low visibility, with 1/2 mile visibility and light rime icing reported. While witnesses noted a momentary engine power interruption at the point of deviation, investigators found no evidence of engine power loss at the time of the impact. Radar data indicated the aircraft's speed fluctuated between 70 and 100 knots during the event.
All seven occupants on board were killed in the accident.
Findings
Investigators determined that there was no evidence of weather-related turbulence at the approach altitude. The investigation focused on several contributing factors, including low ceilings, fog, rain, and night conditions. A primary factor identified was the presence of light airframe icing.
Findings also highlighted that the pilot failed to maintain adequate airspeed and directional control. The aircraft's speed dropped to 70 knots prior to impact, which was below the minimum controllable airspeed (VMCA) of 74 knots. The loss of control is attributed to a combination of insufficient airspeed and icing conditions.