The B-150/MD11/CI642 Accident Investigation Report released by Hong Kong CAD
The Civil Aviation Department (CAD) of Hong Kong that in charge of the investigation occurred on August 22, 1999 published the CI642 accident investigation report on February 4, 2005.
The report stated that the cause of the accident was the commander’s inability to arrest the high rate of descent existing at 50 feet radio altitude.
The probable contributory causes to the high rate of descent were:
(i) The commander’s failure to appreciate the combination of a reducing airspeed, increasing rate of descent, and with the thrust decreasing to flight idle.
(ii) The commander’s failure to apply power to counteract the high rate of descent prior to touch down.
(iii) Probable variations in wind direction and speed below 50ft RA may have resulted in a momentary loss of head wind component and, in combination with the early retardation of the thrust levers, and at a weight only just below the maximum landing weight, led to a 20 kt loss in indicated airspeed just prior to touch down.
And a possible contributory cause may have been a reduction in peripheral vision as the aircraft entered the area of landing flare, resulting the commander not appreciating the high rate of descent prior to touchdown.
In accordance with ICAO Annex 13, ASC and NTSB, US were the Accredited Representatives (AR) of this investigation. A team was organized with 6 of the ASC investigators, 4 of CAA inspectors and 6 of CAL technical people were launched to the accident site on the following day of the accident. ASC took part in the investigation progress meetings in Hong Kong and sent representatives to attend the test flights at the MD-11 test flight simulators, in Long Beach, California in coordinated with China Airlines and Boeing test flight crew. ASC also attended the briefing of the draft report and the new wind data-discovering meeting for the new wind direction & wind speed information.
The accident draft report was completed in 2003. Both China Airlines and Boeing Company had different opinions with respect to the probable causes of the accident, and appealed to the Hong Kong Court according to CAP. 448 Hong Kong Civil Aviation (Investigation of Accidents) Regulations, regulation 11. and Part III regulation 12, for review. The Hong Kong Court organized a Review Board with invited aviation experts and held public hearings from November 17 to 27, 2003.The Board of Review report was finished and sent to the Chief Executive of Hong Kong government in December 2004.The conclusions of the Board Review confirmed most of the findings of the Hong Kong final report.
ASC’s comments to the final report are follows:
• From FDR data, 21 feet prior to touchdown, the elevator was pulled up from 5.5 degrees to 15.73 degrees. However the descent rate was increased continuously. The high descent rate was probably affected by the unsteady wind;
• The description of Boeing’s manual to auto-throttle operation in adverse weather was not fully comprehended;
• The wind at landing area of 25L was affected by the wind passing over the passenger Terminal. Suggest Hong Kong to upgrade the wind shear and turbulence detection system equipments.
Hong Kong has attached ASC’s comments to the final report in accordance with the ICAO Annex 13.
ASC respectfully agrees with the Hong Kong investigation report and will follow up the implementation of safety recommendations.
Civil Aviation Department Hong Kong