The structural failure analysis of the Titanic I completed for ESG 312 based on the findings of Tim Foecke from the Metallurgy Division at the National Institute of Standards and Technology for the U.S. DEPARTMENT OF COMMERCE.
The American Airlines Flight 191, May 25, 1979, crashed moments after takeoff from Chicago. This disaster resulted in the deaths of all 258 passengers, 13 crew members, and two people on the ground. It is recorded in the top ten worst aviation disasters in history.
During takeoff, one of the engines separated from the wing and flipped over the wing as it continued to separate from the aircraft. In doing so, it severed hydraulic fluid lines. While the aircraft was attempting to gain altitude, the left wing aerodynamically stalled while the right continued to produce lift, causing the jetliner to roll left and become partially inverted.
This disaster has been linked to faulty maintenance causing damage to the pylon rigging structure. I was concluded that the pylon attachment was damaged before the crash, during the last maintenance on it eight weeks prior when the engine was removed from the aircraft using a forklift. McDonnell Douglas did not recommend this procedure and had advised American Airlines not to continue performing maintenance in this way, but they do not have the power to enforce a specific method amongst their customers of the plane.
The damage could be considered due to poor design in that the disassembly for maintenance could be easier, leading to less possibilities of failure. During the maintenance of this specific case, when crews took off the engine, the pylon was dammed on the wing. Further investigation showed damage to the wing's pylon mounting bracket and that the pylon attachment fitting had come into contact with the pylon mounting bracket. This could only occur if the engine were receiving outside support, meaning that the damage had taken place before the aircraft had taken off during maintenance.
The fatigue crack developed over the duration of other flights and did not lead to an immediate failure.
Engineers are using a Design for Reliability (DFR) approach. This involves three main points:
"1) Reliability must be designed into products and processes using the best available science-based methods.
2) Knowing how to calculate reliability is important, but knowing how to achieve reliability is equally, if not more, important.
3) Reliability practices must begin early in the design process and must be well integrated into the overall product development cycle."
While quality control focuses on the product working as designed, reliability control focuses on the probability that the product will continue to work as designed for the period of time it is need without failure, or more simply, how long it will work as intended.