Don t focus on the problem

Transcription

1 Cause Mapping Problem Solving Incident Investigation Root Cause Analysis Hubble Space Telescope Don t focus on the problem Find the best solutions by controlling the causes. Angela Griffith, P.E. webinars@thinkreliability.com Office Houston, TX Tips to Better Problem Solving Overview Construction & assembly spans a decade April 24, 1990: Launched on Space Shuttle Discovery June 1990: Flaw on main discovered, reducing ability to focus The was too flat near the edge by about 1/50 th the width of the human hair... Images of objects such as stars, planets and galaxies were blurred February 11, 1997: Space Shuttle Discovery launched to fix the Hubble Copyright ThinkReliability

2 Conventional Problem Solving 1. Identify the Problem Blurred images/ mission failure. 2. Identify the Root Cause Flaw on the main. 3. Identify the Solution to the Root Cause Fix the flaw on the main. Subtle Difference, Significant Improvement Problem Analysis Solutions Conventional Problem Solving 1. Identify the Problem 2. Identify the Cause (Root Cause) 3. Identify the Solution Cause Mapping Method 1. Identify the Impact to the s 2. Identify the Causes (Cause Map) 3. Identify the Best Solutions Copyright ThinkReliability

3 Cause Mapping Problem Solving Steps 1. Problem Step 1. Problem Outline What When Where GOALS Step 2. Cause Map 2. Analysis 3. Solutions Step 3. Solutions Possible Solutions BEST Solutions Action Plan No. Cause Solution Owner Due Date Controlled Cause Action Item Cause Mapping Why? Why? Why? Why? Why? Because Because Starts with the Impact to the s. Builds backwards through time. Collects and organizes all the Why? questions. Copyright ThinkReliability

4 Cause Mapping Because Because Both causes required to produce the effect Cause Map What When Problem(s) Date Differences Where Physical Location Component Task Being Performed Impact to the s Safety Materials & Labor Compliance Frequency Hubble telescope out of focus, flaw in April 24, 1990 Hubble launched June 21, 1990 Announced flaw in System not tested prior to launch Low Earth Orbit Main Imaging System Initial on-orbit testing None Potential loss of mission objectives Flaw on Mirror built incorrectly This incident First time this issue seen $ 2,000,000,000 $ 2,000,000,000 Copyright ThinkReliability

5 Cause Map Problem Potential loss of mission objectives Hubble images blurred Flaw in primary Error in device used to shape Device was assembled incorrectly Cause Map Potential loss of mission objectives Hubble images blurred Flaw in primary Error in device used to shape Device was assembled incorrectly Relied on single device to verify shape Flaw not found prior to deployment No independent testing Copyright ThinkReliability

6 Cause Map Solution: Change instruments to match flawed Potential loss of mission objectives Hubble images blurred Instruments on spec Problem Error in device used to shape Device was assembled incorrectly Light entering instruments off spec Flaw in primary Relied on single device to verify shape Flaw not found prior to deployment No independent testing Lesson: Don t limit solutions by focusing on the problem or the cause. The best solutions may control a cause that s not even considered a problem. Focus on the Cause-and-Effect Principle - Start the analysis with the impact to the s (deviation from ideal state). - Identify the causes (plural). - Consider alternatives, options to control causes (possible solutions). - Select the best solutions to meet the overall goals. - Prioritize the possible solutions, not the causes. Trying to label the problem or the cause limits the possible solutions. Copyright ThinkReliability