Accident Sequence
The captain, acting as the flying pilot, conducted a night landing on runway 01 in instrument meteorological conditions (IMC). Conditions included a right crosswind from 110 degrees at 14 knots gusting to 18 knots, drizzle, and a wet runway. The flightcrew calculated Vref as 122 knots and Vapp as 128 knots. Digital flight data recorder (DFDR) data indicated the airplane was on autopilot passing the middle marker at 200 feet AGL at 130 knots on the ILS approach. Approximately 3 seconds after the first officer called "runway in sight twelve o'clock," the captain disconnected the autopilot at a radio altitude of 132 feet and a heading of about 18 degrees. Within about 11 seconds after disconnect, the glideslope and localizer deviation increased. The first officer then called "runway over there." About 5 seconds before touchdown, the airplane rolled right, then left, then right.
Landing and Overrun
DFDR-based performance calculations showed the airplane crossed the threshold at an altitude of 35 feet and 130 knots. Touchdown occurred 2,802 feet from the approach end of the 5,495-foot runway (which had an 844-foot displaced threshold) at 125 knots on a heading of 10 degrees. The airplane overran the runway and struck a ditch located 175 feet beyond the departure end. The landing roll calculations indicated a ground roll of 2,693 feet after touchdown, consisting of 1,016 feet before braking was initiated and 1,677 feet after braking until the airplane exited the pavement. According to Saab, for a wet runway, the aircraft would have needed 1,989 feet from the time of braking initiation to stop completely.
Operational Procedures
The American Eagle Airlines FAA-approved aircraft operating manual (AOM) stated that stabilized approaches are essential when landing on contaminated runways. For landing under adverse weather conditions, the desired touchdown point is 1,000 feet from the approach end of the runway. It instructed pilots to cross the threshold at Vapp, then bleed off speed to land approximately Vref minus 5 knots, use reverse if needed, and apply maximum and steady brake pressure to achieve maximum braking effect on a wet runway.
Runway and Safety Area
In 1992, the City of Killeen submitted a proposal to extend the north end of runway 01 by 194 feet. The FAA originally disapproved because the extension would decrease the length of the runway safety area (RSA), which was already shorter than the recommended 1,000 feet for a Part 139 certificated airport. The proposal was later approved, and a drainage ditch was installed in the north RSA, perpendicular to the runway and approximately 175 feet north of the departure end. The airport received FAA Part 139 certification in 1993. FAA airport certification inspection reports from 1998 and 1999 noted the inadequate RSA, but neither letter of correction from the FAA to the City of Killeen mentioned the RSA.
Post-Accident Findings
Following the accident, the ILS runway 01 was flight checked by the FAA, and all components were found operating within prescribed tolerances. Examination of the airplane revealed no anomalies that would have prevented it from operating as designed prior to departing the runway and encountering the ditch.