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Scott Paton

Quality Insider

The Heart of the Matter

Sucking blame out of root cause analysis

Published: Wednesday, November 11, 2009 - 05:00

During my sabbatical from writing this column this summer, I watched an interesting program on the National Geographic Channel’s “Mayday” series1. It serves as a terrific example of how a good root cause analysis can get to the heart of a seemingly complicated problem.

The show focused on the details of British Airways flight 5390, which left the U.K.’s Birmingham International Airport for Malaga, Spain, on June 10, 1990. About 13 minutes into the flight, the left windscreen blew out, sucking the pilot halfway out of the aircraft. (The pilot had unbuckled his shoulder harness after takeoff.) The pilot’s feet caught on the flight controls and a flight attendant who happened to be in the cockpit grabbed the pilot’s waist, keeping him from being completely sucked out of the aircraft. The pilot was bent backward over the top of the aircraft in a 500-mph freezing-cold slipstream with little oxygen.

Meanwhile, the aircraft was diving uncontrollably through some of the world’s busiest airspace. The cabin had filled with condensation and debris was flying everywhere. Fortunately, after a few minutes, the co-pilot was able to regain control of the aircraft, contact air traffic control, and land the plane safely about 20 minutes later in Southampton. Miraculously, the pilot survived the incident with relatively minor injuries. The flight attendant who held onto the pilot also suffered minor injuries. No one else onboard the aircraft was injured.

This is a fascinating story with a happy ending. It makes for gripping television, but the most interesting part of the incident for me wasn’t the accident; it was the subsequent investigation into its cause—the root cause analysis.

The investigation into the accident focused on why the windscreen had blown out of the cockpit. This aircraft, a BAC-111, had an unusual design in that the windscreen was attached to the outside of the aircraft with 90 retention bolts. Most other aircraft have their windscreens attached to the inside of the cockpit, which prevents them from being sucked out of the aircraft. But, hundreds of other BAC-111s had the same design and their windscreens had not failed. The investigators soon discovered that the windscreen had been replaced 27 hours before the flight. Naturally, they turned their attention to the shift maintenance manager who had replaced the windscreen.

Instead of walking in and asking the shift maintenance manager what he had done wrong, the investigators took a different approach. They brought a psychologist with them to aid in their interview. They didn’t accuse or fix blame. They made him part of the investigation to determine the cause. They asked him what he had done on the day he had replaced the windscreen and why he thought it had failed. This approach put him at ease and led the team to discover exactly what had transpired.

The maintenance manager revealed that rather than check the part specifications on the bolts, he simply removed them, walked to the parts crib, and grabbed bolts that looked like the ones he had removed. Incredibly, the parts manager told him that he had grabbed the wrong bolts, but the maintenance manager ignored his advice.

The investigation team discovered that 84 of the 90 windscreen retention bolts were 0.026 inches too small in diameter, while the remaining six were 0.1 inches too short.

The team also discovered that the shift maintenance manager had some good reasons for doing what he did: the maintenance documents were located across the airport from where the maintenance work was being done. The previous installation of the windscreen had also been done incorrectly, so the bolts that the maintenance manager replaced were also the wrong size. There was no one available to verify that he had done his work correctly with the proper parts. In addition, he was working alone very early in the morning in a dark aircraft hanger.

Undoubtedly, the team would have discovered this information without the maintenance manager’s cooperation, but because of their nonconfrontational approach and by making the maintenance manager a part of the investigation, they got to the root cause very quickly.

How many times do we affix blame first when doing root cause analysis? Sure we may find out why the problem occurred but are we overlooking additional underlying causes and creating additional problems because employees are afraid to tell us the whole story?

Using your heart just might help you get to the heart of the matter.



1. Originally produced in Canada as “Mayday -- Air Disaster” and in the United States as “Air Emergency,” episode “Blow Out” aired Sept. 14, 2004. http://en.allexperts.com/e/a/ai/air_crash_investigation.htm


About The Author

Scott Paton’s picture

Scott Paton

Scott Paton is Quality Digest’s editor at large and president of Paton Professional, a provider of books, videos, webinars, and other resources for quality professionals.


Look at the Process First

Excellent article....and a very interesting story.
Sandra Gauvin