On April 1, 2011, about 15:58 mountain standard time (MST), a Boeing 737-3H4, N632SW, operating as Southwest Airlines flight 812 experienced a rapid decompression while climbing through flight level 340. The rapid decompression occurred due to a failure of the outside skin of the aircraft.
Read the NTSB report and data summary on this accident below. Some areas have been highlighted in the Final report that may help you with this case study.
Now, this is not the first time this has happened in aviation and surely not in the case of the B-737. Those old enough to remember will recall Aloha Airlines flight 243 in 1988. A flight attendant was lost in that accident when the entire top half of the fuselage (about a 20 foot section) ripped off the aircraft in flight. In 2009, another Southwest B-737 (flight 2294) experienced a similar incident. And as recent as April of 2018, a Southwest Airlines 737 (flight 1380) had a window blow out after an uncontained engine failure resulting in the death of a passenger. Feel free to look these up and use any information on these other accidents if you like.
The reason for this accident came down to a fabrication error from back in 1996 when the aircraft was manufactured. The NTSB found that the crown skin was replaced during the manufacturing process, and is was done improperly.
After what you have learned about the cause of this accident, and the others if you want to incorporate or use them, use one of the methods of analysis that you learned about in this module to complete an analysis of the possible failures that could happen in this process and the outcomes if that failure were to happen.
Now, it is important to note here that the human operator can be part of the system. In other words, the human can be a subsystem too. If that operator has some form of interface that can affect the overall operation of the system (like when the holes were drilled), they can be one of the nodes used in the analyzing technique. Provide your analysis and a narrative of your findings in an analysis to your boss. Use any other sources of information you need to research the accident further, but be sure to cite them accordingly.
This assignment has two requirements that must be completed.
- A chart presenting the data you selected to analyze in your chosen technique (examples are found in the Ericson text).
- A short narrative to the boss telling them why the items you show in your chart are important and need to be addressed.
- MIL-STD-882E, Standard Practice for System Safety by the Department of Defense (DoD – PDF)
- Task 208 – Functional Hazard Analysis