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Human Factors - China Airlines Flight 611

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Ray En Yeo

on 22 July 2013

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Transcript of Human Factors - China Airlines Flight 611

China Airlines 611
General Information
Date of Event: 25th May 2002
Time of Event: 1529 Taipei Local Time
Airline: China Airlines
Aircraft Type: Boeing 747-200
Type of Maintenance: Base Maintenance – Installation of doubler plate on the after lower lobe section of the fuselage

China Airlines Flight CI611 disintegrated mid flight about 23 nautical miles away from Making, Penghu Islands
Two pilots, one flight engineer, 16 cabin crewmembers and 206 passengers on board
Radar contact was lost while aircraft was climbing to alt of 35000ft
All occupants of Flight 611 died
Maintenance Errors
Aircraft incurred tail strike about 22 years before incident

Temporary repairs were conducted immediately and a permanent repair was completed 3 months later

Permanent repair was not conducted within Boeing specifications
Maintenance Errors
Damage done to aircraft was beyond allowable damage for overlap patch repair

Damage was not cut out prior to patch job

Size of doubler was not large enough to cover entire damaged area as cracks propagated over the years
Conclusion of Incident
Lapse in servicing
Engineers did not follow Structural Repair Manual (SRM)
Section 46 (aft) was not removed
Doubler installed was too small
Inspection Errors
No one discovered propagating cracks for 22 years due to the doubler plate concealing them
Nicotine stains suggested there were cracks but inspectors lacked the knowledge
Other Errors
Repair had been logged as complying with SRM, but in actual fact, it was not conformed to the standards
Contributing Factors

Procedures did not adhere to SRM
Chief structure engineer made a decision to stop following SRM to save hassle
Equipment, tools and safety equipment
Magnifying glass was not used during inspection
SRM stated that magnifying glass is needed during structural inspection
China Airlines used high frequency eddy current NDT.
This proved not effective against detecting cracks through a doubler
Job and Task
Task at hand for operator was to cut out and reinforce it with a 125” X 23” doubler

Job was very different and difficult compared to normal repairs

Methods used to repair aircraft was similar to temporary repair
Individual factors
Staff should look for person in charge when they met with difficulties adhering to SRM

If problem goes beyond SRM specs, more info can be obtained from Boeings' Field Service Representatives

Staff were complacent and carried out repair works without seeking further clarifications although in doubt
Technical knowledge and skills
Clear brown stains were formed along the doubler plate
Passengers were allowed to smoke inflight
Nicotine seeped out cracks due to pressure difference
Indicated that a crack was present
Maintenance crew lacked knowledge
Environment and facilities
No standards of amount of lighting in hangar

Inspection requires many different types of lighting to make sure visibility is not affected

Without these standards, safety and results of inspection is greatly affected
Organizational Factors
Normal work procedure was not followed
Permanent repair was required; quality of repair carried out was only of temporary repair standards
Repair works of aircraft had been logged incorrectly

Organizational Factors
Corrosion Prevention Control Program had to be put into place, but China Airlines did not perform these checks which would had detected the cracks
This allowed aircraft to continue operation with unresolved safety issues
Leadership and Supervision
Boeing deployed Field Service Representative to provide assistance and advice

No evidence that FSR provided information to service crew when performing a permanent repair for tailstrikes
Chief structural engineer informed Boeing’s Field Service Representatives of the obstacles faced

Made a request for the Boeing FSR to inform Boeing

No reply was recieved, therefore he took it that the repair was approved by Boeing

Error prevention strategies
What China Airlines should do in the future:
Conduct maintenance in conjuncture with SRM
Conduct damage inspection with approved procedures
Review record keeping system and make sure logs are accurate
Review repair assessment program and make changes to it
Establish that all compulsory requirements are in place
Maintenance crew is to be reassessed on their skills and knowledge
Reassess relationship with Boeings' FSR to ensure good communication

Error Prevention Strategies
What CAA should do:

Closely monitor all safety-related maintenance documentation

Valuable lesson learnt for China Airlines
Helped improve air safety globally
In the light of this accident, it may have Prevented future accidents and saved more lives.
Error Prevention Strategies
What Boeing should have done:
Review FSR and China Airlines relationship

Make sure FSRs are more proactive

Update inspection methods and tools
Full transcript