Primary finding
Probable cause
Encounter with windshear during landing which resulted in a tailstrike.
Investigator assessment
Analysis narrative
United Parcel Service (UPS) flight 2918 experienced a tailstrike while landing on runway 6 at San Bernardino International Airport (SBD), San Bernardino, California. The non-scheduled cargo flight was operated under the provisions of 14 Code of Federal Regulations Part 121. The airplane sustained substantial damage to the underside of the fuselage near the tail. Flight 2918 was originally destined for Ontario International Airport (ONT), Ontario California. After a missed approach at ONT, the flight crew elected to divert to SBD due to fuel state and unfavorable wind conditions at ONT. According to the flight crew, the approach into SBD was stabilized at both 1,000 and 500 ft above ground level (agl). The flight crew further stated that during landing on runway 6, the captain began a normal flare at about 100 ft agl, but he felt the airplane “nose come up and sink rate accelerate” at about 15 ft. The captain stated the airplane contacted the runway “slightly more firmly than usual” but it did not bounce. Once on the runway, the flight crew received an aural windshear warning. Flight data showed the airplane’s pitch attitude reached a maximum of 8.1° at touchdown, sufficient to cause contact between the airplane’s lower fuselage and the runway. Additionally, flight data showed a vertical acceleration of 2.2g, and a windshear warning simultaneous with the touchdown that lasted about 5 seconds. An unscheduled stabilizer trim movement warning occurred immediately after the touchdown. Lastly, an unscheduled stabilizer movement, consistent with the tailstrike event, occurred momentarily about half a second after touchdown. During postlanding rollout, the captain recalled seeing a “tail skid” message on the engine indicating and crew alerting system (EICAS). During postlanding taxi, the first officer was unable to reset the stabilizer trim. Postlanding inspection by the captain revealed substantial damage to the lower fuselage consistent with its contact with the runway. Further inspection of the airplane found damage to the tail skid shock strut and its support assembly as well as the horizontal stabilizer ballscrew actuator (jackscrew), both as a result of the tailstrike. The tail skid damage was consistent with the tail skid message observed on the EICAS by the flight crew. The flight data showed no evidence of a mechanical malfunction that would have contributed to the airplane pitch angle when the airplane touched down on the runway.