What happened
The MD-88 was cleared for a visual approach. Upon reaching the visual descent point, the flight crew transitioned to the Visual Approach Slope Indicator (VASI). While the pilot reported that the aircraft was stabilized during the approach, the first officer noted a higher than normal sink rate as the aircraft neared the touchdown point. Consequently, the airplane touched down hard on the runway. The pilot later stated that the aircraft touched down sooner than expected.
The investigation
An examination of the airframe identified structural damage located between fuselage stations 1338 and 1351. Data retrieved from the digital flight data recorder (DFDR) provided a comparison between this incident and the three previous landings. The readout revealed several significant deviations:
- The nose-up stabilator trim was twice as steep as in previous landings.
- The touchdown airspeed was 8 to 14 knots lower than usual.
- Nose-up elevator deflection was two to three times larger.
- The maximum pitch attitude at touchdown was two to five times higher than previous operations.
According to the MD-88 takeoff and landing booklet, the required landing airspeed for this flight should have been 133 knots.