What happened
While being vectored for an approach to runway 3R at Detroit Metropolitan Wayne County Airport, the turboprop aircraft descended into a level field in a rural area approximately 19 nm southwest of the airport. The aircraft struck the ground in a steep, nose-down orientation. The flight was carrying 26 passengers and 3 crew members, and the impact and subsequent fire resulted in 29 fatalities and 0 survivors. At the time of the accident, the aircraft was operating under instrument meteorological conditions.
Findings
Investigation results indicated that the aircraft likely accumulated a thin layer of glaze or mixed ice on the leading edge deicing boots as it descended from 7,000 feet to 4,000 feet. This ice formation, which may have included ice ridges on the upper leading edge, might have been difficult for the crew to detect. As air traffic control instructed the aircraft to reduce speed to 150 knots, flight data showed the plane began to depart from controlled flight while decelerating between 155 and 156 knots in a flaps-up configuration.
Several systemic issues were identified, including inadequate FAA certification processes regarding the icing characteristics of turboprop-driven transport airplanes. Specifically, the certification did not require manufacturers to prove flight handling and stall capabilities under realistic ice accretion scenarios. Furthermore, while the manufacturer had updated the flight manual in April 1996 to recommend activating deicing boots at the first sign of ice, the operator had not implemented this change because it conflicted with established company practices. Discrepancies were also noted in how the company communicated minimum airspeed requirements, leading to pilot uncertainty regarding appropriate speeds during icing conditions.