July 14, 2009 | Mark Paradies

Maintenance Error Causes $3.9 Million Damage to Air Force MQ-9 Reaper

According to a news release about an Air Force accident report, an incorrectly assembled valve caused a severe oil flow imbalance that resulted in the failure of the engine of the MQ-9 Reaper during a training flight. The remote pilot attempted to land the malfunctioning aircraft on a remote dessert landing strip and the resultant hard landing and overshooting the strip caused $3.9 Million in damage to the Reaper. I have not seen the report but a cause in the press release –

improperly assembled oil system temperature control valve

Doesn’t sound like a root cause. Rather, it seems like a causal factor that would be the result of an Equifactor® equipment troubleshooting evaluation.

To find the root cause, the causal factor of “technician incorrectly assembles valve” would need to be analyzed using the Root Cause Tree®.

I would bet that this would turn out to be a Human Performance Difficulty and the 15 Questions on the front side of the tree would help the investigator dig into the reasons for the maintenance error. A sample of the questions that would need to be looked into would include:

  • Was the technician fatigued?
  • Was the procedure used?
  • Was the procedure difficult to use?
  • What were the human factors involved in the work?
  • Was the training adequate?
  • Were their any communication issues?

This would lead to more in-depth analysis of the apoplicable seven Basic Cause categories (Procedures, Training, Quality Control, Communications, Management Systems, Human Engineering, and Work Direction).

This in-depth analysis would probably lead to several root cause – all of which, if corrected, are potential opportunities to apply best practices to improve performance and prevent a future maintenance error (saving millions of dollars).

I’ll try to find out more about this investigation and post any new information here.

If you would like to learn how to perform an advanced root cause analysis using TapRooT® and Equifactor® attend the 3-Day TapRooT®/Equifactor® Equipment Troubleshooting and Root Cause Failure Analysis Course.

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Root Cause Analysis
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