Flight and Crew
China Airlines' scheduled passenger flight CAL605 departed Taipei (TPE), Taiwan at 02:20 for the 75-minute flight to Hong Kong-Kai Tak. The departure and cruise phases were uneventful. During the cruise, the commander briefed the co-pilot on the approach to Hong Kong using the airline's own approach briefing proforma. The briefing covered the runway-in-use, navigation aids, decision height, crosswind limit, and missed approach procedure. The commander paid particular attention to the crosswind and stated that, should they encounter any problem during the approach, they would go-around and execute the standard missed approach. He did not discuss the autobrake setting, reverse thrust power setting, or actions in the event of a windshear warning from the Ground Proximity Warning System (GPWS).
Approach and Landing
Weather reports indicated strong gusty wind conditions, rain, and windshear. On establishing radio contact with Hong Kong Approach Control at 03:17, the crew were given radar control service to intercept the IGS approach to runway 13, which is offset from the extended runway centerline by 47°. After intercepting the IGS localiser beam, the pilots changed frequency to Hong Kong Tower and were informed by the AMC that visibility had decreased to 5 kilometres in rain and the mean wind speed had increased to 22 kt. Two minutes before clearing CAL605 to land, the controller advised the crew that the wind was 070/25 kt and to expect windshear turning short final.
During the approach, the pilots completed the landing checklist for a flaps 30 landing with the autobrakes controller selected to position '2' and the spoilers armed. The reference airspeed (Vref) at landing weight was 141 kt; to that speed the commander added half the reported surface wind to give a target airspeed of 153 kt. Rain and significant turbulence were encountered. At 1,500 feet, the commander noted the FMC-computed wind speed was about 50 kt. At 1,100 feet, he disconnected the autopilots and commenced manual control. At 1,000 feet, he disconnected the autothrottle due to dissatisfaction with its speed holding. Thereafter, he controlled the thrust levers with his right hand and the control wheel with his left. The commander had difficulty reading the reference airspeed on his electronic Primary Flying Display (PFD) because of an anomaly, but the co-pilot rectified this by re-entering 141 kt into the FMC.
Shortly before the visual right turn onto short final, the commander saw an amber 'WINDSHEAR' warning on his PFD. Just after the start of the finals turn, the GPWS gave an aural warning of "GLIDESLOPE" (indicating the aircraft was significantly below the IGS glidepath), then a second later "WINDSHEAR" repeated twice. Both pilots saw 'WINDSHEAR' in red on their PFDs. Abeam the Checkerboard, the commander was aware of uncommanded yawing and pitch oscillations. He continued the turn without speaking while the co-pilot called speed deviations from 153 kt. At the conclusion of the turn, both pilots were aware the aircraft had descended below the optimum flight path indicated by the PAPI system.
The air traffic controller watched the final approach and landing. The aircraft appeared on or close to the normal glidepath as it passed abeam the tower and touched down gently on the runway just beyond the fixed distance marks (300 metres beyond the threshold) but within the normal touchdown zone. The controller could not see details due to water spray but tracked it on Surface Movement Radar, noting it was fast as it passed the penultimate exit at A11. At that time, he observed a marked increase in water spray and the aircraft began to decelerate more effectively. The commander stated the touchdown was gentle and near wings level. Neither pilot checked that the speed brake lever, which was 'ARMED', had moved to 'UP' on touchdown.
Post-Touchdown Events
A few seconds after touchdown, after the nose wheel was lowered onto the runway, the co-pilot took hold of the control column with both hands to apply roll control against the crosswind from the left. The aircraft then began an undesired roll to the left. The commander instructed the co-pilot to reduce the into-wind roll control and physically assisted to correct the roll attitude. Shortly after corrective action, the aircraft again rolled left, and the commander intervened once more. During the unwanted rolling, which lasted about seven seconds, the aircraft remained on the runway with at least the left body and wing landing gears in contact. After aerodynamic control was regained, the co-pilot noticed an EICAS message showing the autobrake system had disarmed. He informed the commander and reminded him that reverse thrust was not selected. At almost the same moment, the commander selected reverse thrust on all engines and applied firm wheel braking. As the aircraft passed abeam the high-speed exit A11, the commander saw the end of the runway approaching; both he and the co-pilot perceived insufficient remaining distance. The co-pilot also pressed hard on his foot pedals. Near the end of the paved surface, the commander turned the aircraft left using rudder pedal and nose wheel steering tiller inputs. The aircraft ran off the end of the runway to the left of the centreline. The nose and right wing dropped over the sea wall, and the aircraft entered the sea, creating a large water plume visible from the control tower 3.5 km away.
Evacuation
The controller immediately activated the crash alarm. The Airport Fire Contingent, on standby due to strong winds, responded rapidly with fire vehicles and boats; other vessels also assisted. After the aircraft settled, the commander operated the engine fuel cut-off switches, and the co-pilot operated all fire handles. The commander attempted to contact cabin crew via interphone, but it was not working. The senior cabin crew member arrived on the flight deck as the commander was leaving his seat to go aft. The commander issued instructions to initiate evacuation through the main deck doors, supervised by the senior cabin crew member. Ten passengers were injured, one seriously.
Probable Cause
The accident was the consequence of the combination of the following factors: - The commander deviated from the normal landing roll procedure in that he inadvertently advanced the thrust levers when he should have selected reverse thrust. - The commander diminished the co-pilot's ability to monitor rollout progress and proper autobrake operation by instructing him to perform a n...