What happened
Approximately 26 minutes before landing, the crew received SIGMET 1C, which advised of a line of thunderstorms extending from Milwaukee to St. Louis, moving southeast at 15 knots. The crew also identified a separate thunderstorm located west of the airport. As the aircraft approached approximately 20 miles northeast of the airport, the storm was visible both visually and on radar to the west of the airport.
About 15 miles out from the airport, the crew stopped monitoring the radar due to increasing workload and ground clutter interference. Rain intensity increased significantly during the final approach phase. The aircraft landed but overran the runway, ultimately striking an approach light.
Findings
The investigation highlighted several critical factors contributing to the accident. The crew did not consult the landing field length chart in the company operations manual prior to landing. This chart indicates that a stopping distance of 7,930 feet is required from initial brake application for a 'very wet' runway.
At the time of the accident, another flight arriving in the airport area received vectors north of the airport and held for about 10 minutes before flying on the back side of the weather for an approach to Runway 14R. Runway 27L, which was 10,141 feet long, was available but likely insufficient given the conditions and lack of pre-landing planning.
The failure to account for the extended stopping distance required on a very wet runway, combined with the decision to cease radar monitoring due to workload, played a significant role in the overrun.