Ellington Field Airport
Aircraft Accident/Incident Report

Houston, Texas 77034
Friday, September 11, 1998 6:24 CDT

The night cargo flight was dispatched from the company's main hub into a known area of potentially severe weather, which was influenced by a stationary front and Tropical Storm "Frances." The terminal forecast provided by the operator to their flight crew was 2-days old. The flight crew was not properly briefed on the forecasted weather conditions for the destination airport, and were not provided with all of the adverse weather information and NOTAMS affecting their route of flight and their destination airport. The flight crew missed the first approach to runway 17R due to strong crosswinds. The flight was subsequently vectored for a Category 1 ILS approach to runway 35L. Level 4 to 5 convective activity with tops to 42,000 feet were present over the destination airport at the time of the mishap. The flight crew configured the airplane for an "autoland" approach with the auto-brakes set for maximum braking. A strong crosswind to a quartering tailwind prevailed during the flight's final approach and landing. The airplane touched down 17-feet left of the centerline of the 9,000-foot long ungrooved concrete runway, which was reported to be partly flooded due to its low crown. The auto-pilot was never disconnected by the flight crew and no attempt was made by the flight crew to abort the landing during the accident sequence. The tower had previously reported standing water a the intersection of runway 17R and taxiway Delta during the first approach. The investigation revealed that the runway condition check was conducted by driving a vehicle over the runway centerline for the full length of the runway. The investigation team was on the runway when another torrential rain shower moved across the airport. The team was able to observe a rapid manifestation of water pooling on the runway, mostly away from the centerline. The depth of the water pooling was measured to be at least 7- inches. The investigation team concluded that the issued "standing water" report failed to indicate the severity of the amount of water actually flooding the runway. Heavy rain showers, sometimes described as "torrential" prevailed throughout the area at the time of the accident. Another weather station, located 29 miles to the southeast, reported 7.64 inches of rain from the tropical storm. Witnesses reported the airplane produced a "heavy rooster tail of water" as soon as it touched down on runway 35L. Airport Rescue and Fire Fighting personnel that responded to the accident site, reported that despite the location of their fire house, approximately 1/4-mile across the ramp from the resting place of the airplane, the aircraft was not visible due to the heavy rain that prevailed at the time of the mishap. Some of the first responders reported that "it was raining sideways" at the time of the mishap. Tire marks, similar to "steam cleaning" were found on the concrete surface of the runway, from the touchdown point to the point where the airplane exited the left side of the 150-foot wide runway, were consistent with the tires being in a state of hydroplaning. Nose wheel steering was found to be operational during the landing sequence. Main tire pressures were found to be within inflation limits (185 to 200 PSI). Two of the main tires (no. 3 and no. 7) were damaged and deflated during the accident sequence. One tire showed some discoloration (bluing). On-board avionics test equipment did not record any faults with the autoland system during the accident flight. Examination and bench testing of the eight brake assemblies did not reveal any anomalies. The eight wheel transducers were also tested by the manufacturer and were found to be within limits. The anti-skid/auto-brake control unit was also tested and found fully functional. Flight data recorder data, as well as tire prints made by the nose wheel tire on the runway revealed that the inter-connect between the rudder and the nose wheel assembly attempted to steer the aircraft toward the localizer course. All navigational aids associated with the instrument approach were reported as operating normal during the two approaches. There was sufficient fuel on board to proceed to the alternate airport.

The flight crew's decision to land with convective activity over the airport with a prevailing crosswind to a quartering tailwind, on an ungrooved, flooded runway, which resulted in hydroplaning and a loss of directional control. Factors contributing to the accident were: prevailing dark night conditions; severe weather conditions associated with a major tropical storm, such as convective activity, strong crosswinds, the quartering tailwind, and torrential rain. Also contributing to the accident were the operator's failure to provide the flight crew with up-to-date weather forecasts, in-flight weather advisories, and pertinent NOTAMS relating to the safe operation of the flight.