Narrative:China Airlines flight 5233, a Boeing 747-400, registration B-18723 and operating as a cargo flight, experienced a tail strike during takeoff from Anchorage-Ted Stevens Anchorage International Airport, Alaska, USA. The airplane continued to its intended destination of Taipei-Taoyuan International Airport (TPE/RCTP), Taiwan. There were no injuries to the crew, and the airplane received substantial damage.
When entering the required data into Runway Analysis System, the pilot took the Max Landing Weight as Max Take-Off Weight obtained from Computerized Flight Plan; which led the calculation to provide erroneous take-off thrust, take-off reference speed and take-off model. The aircraft did not obtain enough lift required for take-off, the angles of ground and attack were too large; which caused that the tail had ground contact. During the take-off roll, the pilot had stick shaker warning, then released stick and set the manual thrust to MAX to continue the take-off. In the air the pilot inspected the instruments of cabin pressure and engines which were normal. After landing at 16:48, maintenance personnel checked and found the rear section of aircraft belly had substantial damage
Probable Cause:
Findings Related to Probable Causes:
1. When entering the required data into Runway Analysis System, CM 1 used the data from Computerized Flight Plan but took the max landing weight mistakenly as max take-off weight. Then CM 2 did not cross check to confirm the accuracy of the input data, and did not review all the data after retrieving take off performance figures from Runway Analysis System; so it was not discovered that the max take-off weight that was entered by mistake caused the mal-calculation of take-off thrust, -reference speed and -model.
2. CM 2 entered the erroneous take-off thrust provided by Runway Analysis System into Flight Management System which failed to calculate take-off reference speed; so the columns of V1, VR ,V2 on the page of the take-off speed showed - - - and the pilot did not understand the meaning of - - - , at the end he decided to use the take-off reference speed calculated by Runway Analysis System to enter into Flight Management System.
3. CM 3 has checked Runway Analysis Manual during taxiing to verify the accuracy of the calculation done by Runway Analysis System. However the source of max take-off weight was from the system and not from Weight and Balance Sheet nor Computerized Flight Plan. Therefore it was discovered that the take-off reference speed calculated by Runway Analysis System was much lower than the actual figure that the aircraft should have used.
4. When taking off the aircraft speed reached the VR value calculated by Runway Analysis System, 2 seconds later the aircraft started to roll. Because the actual roll speed of 149 knots/hour was lower than the correct value of 166 knots/hour, the aircraft did not have enough lift required for take-off and angles of ground and attack way too large; which caused the aircraft tail to touch ground.
Accident investigation:
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Investigating agency: | ASC Taiwan  |
Status: | Investigation completed |
Duration: | 1 year and 3 months | Accident number: | ASC-AOR-11-05-001 | Download report: | Final report
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Classification:
Tailstrike
Runway mishap
Follow-up / safety actions
ASC issued 12 Safety Recommendations
Issued: -- | To: China Airlines | ASC-ASR-11-05-001 |
Reinforce flight operation related trainings and tests concerning the timing to perform the take off performance calculation and the procedures for verification, to reduce the risk that pilots maybe use erroneous data for calculations. |
Issued: -- | To: China Airlines | ASC-ASR-11-05-002 |
Review and reinforce the design Runway Analysis System or to use alternative take off performance calculation to reduce the probability that pilots may entered the wrong data. |
Issued: -- | To: China Airlines | ASC-ASR-11-05-003 |
Review and improve the format of Weight and Balance document to reader friendly to reduce the probability that pilots may miss-reading any data. |
Issued: -- | To: China Airlines | ASC-ASR-11-05-004 |
Reinforce trainings and requirements to pilots for acknowledgement of abnormal display from Flight Management Computer (FMC). |
Issued: -- | To: China Airlines | ASC-ASR-11-05-005 |
Reinforce cognitive training to pilots for the danger of aircraft tail touching ground to promote pilots alertness to similar situations. |
Issued: -- | To: China Airlines | ASC-ASR-11-05-006 |
Promote the airlines response, policies and mechanism of the pilots decision making, to ensure pilots to prioritize flight safety when making decisions. |
Issued: -- | To: China Airlines | ASC-ASR-11-05-007 |
Pay continuous attention to international trend related to fatigue management, to promote the control mechanism of fatigue hazards. |
Issued: -- | To: China Airlines | ASC-ASR-11-05-008 |
Reinforce the flight crews resource management training related to communication and coordination, cross-checks, decision-making, response to fatigue and alertness to situations. |
Issued: -- | To: CAA Taiwan | ASC-ASR-11-05-009 |
Supervise airlines to review per the existing operation procedures if the pilots data input and cross-checks are functioning well to avoid any similar cases to occur again. |
Issued: -- | To: CAA Taiwan | ASC-ASR-11-05-010 |
Counsel the airline to pay attention to international trend about fatigue management to promote their control mechanism of fatigue hazards. |
Issued: -- | To: CAA Taiwan | ASC-ASR-11-05-011 |
Supervise the airline to promote their mechanism of response and request pilots to prioritize flight safety when making decisions. |
Issued: -- | To: CAA Taiwan | ASC-ASR-11-05-012 |
Supervise the airline to reinforce the flight crew resource management training related to communication and coordination, cross-checks, decision-making, response to fatigue and alertness to situations. |
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Photos
Map
This map shows the airport of departure and the intended destination of the flight. The line between the airports does
not display the exact flight path.
Distance from Anchorage-Ted Stevens International Airport, AK to Taipei-Taiwan Taoyuan International Airport as the crow flies is 7462 km (4664 miles).
This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.