All posts by ThinkReliability Staff

ThinkReliability are specialists in applying root cause analysis to solve all types of problems. We investigate errors, defects, failures, losses, outages and incidents in a wide variety of industries. Our Cause Mapping analysis method of root causes, captures the complete investigation with the best solutions all in an easy to understand format. ThinkReliability provides investigation services and root cause analysis training to clients around the world and is considered the trusted authority on the subject
Root Cause Analysis - Incident Investigation

Greece Economic Woes – Part 2

By ThinkReliability Staff

In our previous blog about Greece’s economic woes, we looked at some of the impacts the recent events have had on Greece and potentially the rest of the European Union (EU) and a timeline of the events that are part of the ongoing economic crisis.  However, we stopped short of an analysis of what contributed to these impacts.

The outline, which we filled out previously, discusses an event or incident with respect to impacts to the goals of a country (economy, company, etc.).  An analysis of the causes of these impacts can be made using a Cause Map, or visual root cause analysis.  To do so, begin with one impacted goal and ask “why” questions to complete the analysis.  For example, Greece’s financial goal is impacted because its debt rating is just above default.  Why? Because the ratings agencies were concerned with Greece’s ability to repay.  Why? Because their debt to revenue ratio is too high.

Whenever you encounter a situation where a ratio is too high – such as this case, where debt is too high compared to revenue – it means that the Cause Map will have two branches.  Each part of the ratio is a branch.  In this case, if debt to revenue is too high, it means that debt is too high and revenue is too low.  Each branch can be explored in turn.  There have been cases made that only one or the other branch is important, but what we’re looking for in a Cause Map is solutions that can help ameliorate the problem.   Due to the severity of the issue in Greece, solutions that reduce debt and solutions that increase revenue must both be implemented in order to attempt to repair the financial standing.

Greece’s government debt is high – caused by government spending on borrowed money when the euro was strong and interest rates were low.  There are many parts to government spending, which can make their own Cause Map.  Suffice to say, reducing government spending – by a lot – is necessary to reduce the debt to revenue ratio.  Unfortunately, severe reductions in government spending also mean reductions in government services, and government salaries.  As an example, government workers, which total 25% of the total workforce, are seeing their pay reduced 10%.  As you can imagine, this reduced spending has angered some Greeks, causing riots, which have killed Greek citizens.  In this case, the solution “reduced spending” also becomes a cause in another branch of the Cause Map.  It’s important to remember that not all solutions are free of consequences and that solutions themselves may contribute to the overall problems.

Greece’s revenue is insufficient to fuel their current spending levels.   Tax revenue is decreased by tax evasion, high unemployment, and a shrinking economy.  The Cause Map isn’t simple here either, because the shrinking economy contributes to the unemployment rate, and decreased spending can result in decreased revenue.  The worldwide economic woes are contributing to the shrinking economy, but also low levels of foreign investment, caused by what is considered a difficult place to do business due to political, legal, and cultural issues.  Last but not least, many governments in Greece’s situation would devalue their currency in order to regain an economic edge.  However, Greece uses the Euro – so devaluing currency isn’t an option.  There has been some talk of Greece dropping the Euro but a bailout by the other EU countries (itself an impact to the goals) appears to have shelved that discussion for now.

In addition to reduced tax revenue, Greece is having trouble borrowing money.  As their credit rating has fallen (it now has the lowest credit rating in the world), interest rates for loans are climbing, so it is possible that Greece will still fall into bankruptcy and loans will not be repaid. This is caused by the debt to revenue ratio, and adds a circular reference to our map.  This is why the economic issue has been described as a spiral – the causes feed into each other, making it difficult to climb out.

However, Greece has made admirable strides to attempt to reduce their debt and increase their revenue.  Only time will tell if that, and the bailout from the EU, will be enough.

Root Cause Analysis - Incident Investigation

Greece Economic Woes – Part 1

By ThinkReliability Staff

Greece is currently suffering from an economic crisis.  Leaders in Greece, the European Union, and the rest of the world are all anxiously watching as events unfold to attempt to minimize the impact of these issues.  An analysis of this issue can help these leaders minimize their own impacts, as well as provide appropriate aid to Greece.  However, performing an root cause analysis on an issue whose roots reach back years is not an easy task.

Normally a root cause analysis performed as a Cause Map begins with a problem outline.  However, sometimes an issue is so complicated that it’s difficult to begin there.  In these kinds of cases, beginning with the creation of a timeline may aid in the investigation.

What to include in the timeline is a frequently asked question.  When beginning a timeline, put in all the information you have.  It may make sense to go back later and create a less detailed timeline.  However, many events that don’t initially seem to add much to the timeline may later turn out to be important in the analysis.  In the case of Greece, I began the timeline with Greece’s entry into the European Union (EU).  While it wasn’t clear initially whether this contributed to the current issues being faced by Greece, it later became clear that the restrictions placed on EU-member countries did in fact contribute to the current issues.

Events in the timeline may turn out to be impacted goals.  For example, at various points in the timeline Greece’s credit rating has been downgraded.  The last downgrade occurred just before default by Moody’s.  Having a solid credit rating is an important goal – so a downgraded credit rating, especially one as low as Greece’s, is an impact to the financial goal of that country.

Once the timeline has begun (it’s not really complete until the issue is considered resolved, which in this case will take years), the next step would be to tackle the outline.  Writing the timeline will hopefully have provided some clarity to the issue.  For example, since Greece entered recession in 2009, we can choose 2009-2011 as a logical time to enter in the outline.  If more detail is desired, referring to the timeline is also appropriate.

The most commonly asked question about the outline is what to write in the “differences” row.  Differences are meant to capture things that may have been out of the ordinary, or potentially answer the question “why this country (or equipment or time) as opposed to some other country?”  Because Greece is a part of the European Union, which has consistent financial goals for its members, we can use some data points that show how Greece differs from other countries in the EU, or essentially answer the question “why is Greece having these issues instead of the other EU countries?”  In Greece, debt is estimated to be 150% of the Gross Domestic Product (GDP).  This is much higher than for most other nations.  The public sector in Greece accounts for about 40% of the GDP, also higher than typical.  Greece has the second lowest Index of Economic Freedom in the EU, which impacts its ability to quickly adjust to economic changes.   Greece economic statistics were (significantly)   misreported, contributing to the rapid decline in stability.  And, Greek tax evasion is estimated at 13B Euros a year.  This is likely not a full list of the differences between Greece and other EU countries, but it’s a start  and the outline can continue to evolve as more information is provided on the issue.

Once the top portion of the outline is complete, the impacts to the goals can be addressed.  Again, many of these impacts can be pulled from the timeline.  There were some citizen deaths associated with rioting as a result of proposed economic policies, which is an impact to the safety goal.  Spending cuts and tax increases impact the customer service goal (in this case, the “customers” are the citizens of Greece).  The production goal is impacted because of high (above 16%) unemployment, and the financial goals are impacted by a debt rating just above default and a 110B euro default.  Last but not least, there is the potential for impact on the European Union if the crisis spreads beyond Greece.

As you’ve noticed, no real analysis has yet taken place.  We’ll look at some of the causes contributing to the      current issues in Greece in an upcoming blog.  Click on “Download PDF” above to view the timeline and outline

Root Cause Analysis - Incident Investigation

Foreclosures Down?

By ThinkReliability Staff

At first glance, it might appear to be a welcome story.  After years of decline in the housing market, there has been a significant dip in foreclosure filing rates.  However the real reason behind the dip isn’t economic recovery…it’s a backlog of work at banks across the nation.  A visual Cause Map helps illuminate what is really going on.

Foreclosure filings have dropped 25% in the last six months of 2010.  This normally would mean that fewer properties require foreclosure.  Banks usually notify homeowners within days of the first missed payment.  After multiple missed payments, the Notice of Default is finally sent to the homeowner, about 2 months after the initial missed payment. If the homeowner doesn’t pay up, that’s followed soon after by a foreclosure filing.  In most states, eviction can happen in as little as 120 days.

However in today’s economy, banks are slower to take on new foreclosures.  One of the major causes – a huge backlog of vacant properties – has made banks reluctant to notify newly delinquent homeowners.  The initial notification process has slowed down, but so has the entire foreclosure process.  Banks hope that by delaying the process, homeowners may be able to resume payment – the preferred outcome.  In some states, foreclosures are averaging well over 900 days.  Banks are in the business of managing money, not property.

There’s another reason behind the processing delays.  Last fall banks were brought to court for robo-signing, a practice where law firms were automatically signing off on all foreclosure paperwork.  The practice meant that many applicants were illegally kicked out of their homes.  Many of the largest banks and lenders suspended processing to determine how robo-signing was occurring and stop it.  It turns out that law firms, in an effort to get through the mountains of paperwork, were rubberstamping the foreclosure filings without due diligence to ensure everything was in order.

Delayed foreclosures are beneficial to families facing eviction, however often it is simply delaying the inevitable.  Many economists believe that the economy will continue to struggle until the housing market recovers.  In the meantime, the foreclosure crisis will drag on until banks can close out these dysfunctional loans.

Root Cause Analysis - Incident Investigation

City Facing Default

By ThinkReliaiblity Staff

A small Rhode Island town is on the brink of financial disaster.  A low tax basis and mounting liabilities are leaving Central Falls with few options short of filing for bankruptcy protection.   The town has requested financial assistance from state and federal governments and is begging pensioners to accept lower benefits.  But how did they get to this point, and what can be done to keep neighboring towns – and the state itself – from bankruptcy?  A Cause Map visually shows how this occurred.

Like other towns facing financial difficulty, Central Falls accepted more debt than they are now able to pay.  This two-fold reason is at the center of the Cause Map.  All of the effects Central Falls now faces – such as closed town services and the loss of local jobs – stem from the fact that the city had to cut spending.  The city had to cut spending because it is facing bankruptcy.  The Cause Map method allows us to trace the reasons back even further and build a complete picture.

The first piece is that the town has a large debt – $80M to be exact – in pension liabilities for its 214 city police officers and fire fighters; this is in addition to $25M in budget deficits over the next five years.  The generous pensions can be traced back to two state laws regarding public worker negotiations.  Rhode Island is one of the few states that allows workers unlimited collective bargaining, meaning that workers can negotiate for a higher salary for any reason.  Without any limits, talks often broke down.  When talks broke down arbitrators stepped in, and their decisions were binding.  In past years, arbitrators often settled on benefits that were comparable to surrounding towns instead of what the city could actually afford.  Unlimited collective bargaining and binding arbitration together contributed to the poor negotiations and overly-generous benefits.

The second piece is that the town doesn’t have a large income.  It has a small tax basis since the median family income is only around $33,000.  Other sources of income have been pulled back as well – like state and federal funding.  The state is facing similar issues, and is in no place to bail out the multiple municipalities at risk.  The federal government had extended aid, but rescinding it when Central Fall’s credit rating was downgraded by Moody’s.

Municipal bankruptcy is a rare occurrence, with fewer than 50 occurring in the last 3 decades nationwide.  State bankruptcy is practically unheard of.  Arkansas was the last to default on its bonds, following the Great Depression.  This is in part to bankruptcy laws put in place after to avoid such an occurrence.  When one town goes bankrupt, neighboring communities are often negatively affected.  The resulting domino effect could be disastrous.  Rhode Island is a small state with little room to maneuver if local towns – like Central Falls – start going bankrupt.

Root Cause Analysis - Incident Investigation

Record Flooding in Minot, ND

By ThinkReliability Staff

Record flooding has struck along the Souris River, leading to record-breaking flooding in Minot and threatening multiple other towns.  The river has widely ranging annual flow rates, varying from 4,200 acre feet to 2.1M acre feet.  Flooding is not uncommon in this part of the country, but what is striking about this case is how events upstream contributed so dramatically to what happened in Minot.

Rivers have always flooded.  Snowmelt and spring rains naturally contribute to higher flow rates.  Rivers also naturally move, as soil erodes in places and builds up in others.  As communities have developed near rivers, a need arose to control the rivers’ boundaries.  After all, you didn’t want to have your farm land constantly submerged by water.  Civilizations have been using earthen structures – like levees or dikes – for thousands of years to control the flow of water.

It was only within the last century, that extensive man-made levees have been built within the U.S.  The levees along the Mississippi River are some of the most elaborate in the world, extending 3,500 miles.  Along with levees, dams help to regulate the flow of water.  Dams can create artificial lakes used either to prevent flooding downstream or to provide a source of water for the community.

How is all of this relevant to the flooding in Minot?  A visual Cause Map can shed light on what led to the intense flooding there.  For starters, the levees meant to keep the Souris River contained were both overtopped and breeched.  This occurred because there was a high volume of water flowing downstream over an extended period of time.  Why is that?

The Souris River actually begins in Saskatchewan, where a further series of levees and dams controls the river.  Southern Canada had a significant amount of snowmelt and spring precipitation, saturating the soil and filling up local lakes and man-made reservoirs.  The area also had a heavy amount of rainfall the preceding the weekend, 4 to 7 inches.   With reservoirs already filled, officials had no choice but to increase dam flow rates to prevent flooding or worse – a burst dam.

While these complex levee and dam systems usually provide stability for riverside communities, they also can work against some of the systems that evolved in nature to keep water flow in check.  For instance, natural levees develop as rivers periodically overflow and deposit silt.  Also everglades and marshlands act like a sponge absorbing excess water.  Human development has affected these natural processes, and unfortunately there are likely to be many further effects from the flooding as the water continues down the Missouri River Basin.

Root Cause Analysis - Incident Investigation

Changing the Emergency Response Process

By ThinkReliability Staff

When Line 132 ruptured last September in the community of San Bruno, California, emergency personnel were quick to respond to the natural gas explosion.  The first fire truck was on scene within six minutes of the explosion.  What responders found was a chaotic scene, with multiple wounded and killed and swaths of the neighborhood in flames or simply flattened.  Little did they know that a large natural gas transmission line, feeding the spreading fire, was directly beneath them.  Emergency personnel did their best to clear homes and evacuate the wounded as the fire spread, but the confusion continued for nearly 90 minutes until the gas valves were shut off upstream from the fire.

The subsequent National Transportation Safety Board (NTSB) investigations focused on Pacific Gas and Electric (PG&E) processes following the accident, and found that PG&E was woefully unable to respond quickly to a crisis of this magnitude.  As a set of timelines show, emergency response personnel were already on scene long before PG&E was even aware that a pipeline rupture may be associated with a local fire.  PG&E apparently did not notice an alarm warning them of a pressure drop.  Control systems detected a severe pressure drop approximately four minutes after the disruption; however the PG&E gas control center, located in San Francisco, remained unaware of the explosion and fire until a PG&E dispatch center in Concord called them.  Off duty employees had called-in to the Concord dispatch center 7 and 11 minutes after the incident, alerting them of a large fire in San Bruno.  However it was not until the dispatch center called the gas control center 16 minutes after the explosion that gas control operators realized what was happening.  By this point emergency responders had already arrived at the scene, unaware of the large natural gas pipeline directly under the neighborhood.

What information did emergency responders have as they arrived on scene that day?  Although PG&E itself was aware of the likely service disruption, they failed to notify first responders of any potential danger in those critical minutes after the explosion.  Additionally according to NTSB testimony, the fire department was unaware of the large natural gas pipeline under the community.  Larger transmission pipelines have different operating characteristics than smaller distribution pipelines, including different recommended safety precautions and shut down times.  With a better awareness of the pipeline locations and associated dangers, emergency response personnel could have developed training and response procedures ahead of time for an explosion of this magnitude.  PG&E has since taken steps to enhance its partnership with first responders and other public safety organizations.  Clearly there are other steps that need to be taken as well.

When conducting an investigation, a timeline can be a helpful tool to organize information.  While straightforward to build, timelines can identify areas needing more research and aid in building a process map and a Cause Map.  Compare what happened at PG&E to what emergency responders were doing.  You’ll notice there was a significant delay at PG&E in recognizing there was a problem and then acting upon it.  It took nearly 90 minutes to close valves to shut transmission lines.  Changes must be made to speed up PG&E’s procedures in a crisis situation.

Likewise process maps are a useful tool for determining where a process can use improvement.  In the Current process map, it is noticeable that there are three parallel processes occurring, where information is not being shared in an efficient manner.  The PG&E Dispatch Center only shares information with the Emergency Dispatch Center after they have fully assessed the situation.  This information might come after the fact, as it did in San Bruno, or seriously delay an effective response by EMTs and firefighters.  Going one step further, trained emergency personnel might be able to check with local utilities if they have reason to suspect a natural gas pipeline is involved.  Simple procedural changes, such as who is notified and when, can have significant impacts.

It is important to note that the timeline helps create the most accurate “As Occurred” process map (called Current in this case).  Procedures can differ from actual processes, so it is important to document what actually happened, identify differences in what should have occurred, and figure out why it didn’t.  In this case, PG&E’s procedures were followed and need to be revised.

The NTSB recommendations will undoubtedly lead to multiple changes.  It is easy to focus on material solutions, which tend to be expensive to implement.  Some changes under consideration are the use of remote controlled valves and the replacement of aging pipes.  While there is no doubt that these changes need to happen, other changes can help in the meantime.  Process maps can help identify procedural changes which may be much less expensive, such a modifying notification procedures.

A detailed Cause Map built after the preliminary investigation shows what NTSB investigators believe led the natural gas leak.  More information on the NTSB investigation can be found here.

Root Cause Analysis - Incident Investigation

Tornado Season of 2011: Worst Ever?

By ThinkReliability Staff

2011 is on pace to be the worst tornado season since record keeping began in 1950.  Communities nationwide have been affected this year, not just those in “Tornado Alley” where twisters are most commonly found.  The marked increase has many wondering just what is going on.  Is it simply greater media attention?  Or perhaps just bad luck this year?  Or maybe this is all because of global warming…

Weather experts agree that it is a combination of factors, but nothing out of the ordinary.  Weather is cyclical, and a higher number of deadly tornados than usual have touched down this year.  Currently 52 deadly tornados have already struck, compared with an annual average of 22.  Additionally these tornados happen to have stuck heavily populated areas.  As recent as April of this year, the EPA has stated that “to date, there is no long-term evidence of systematic changes in [thunderstorms and tornados] over the course of the past 100 years.”

However, some contend that the higher number of tornados must be tied to climate change.  They argue that all the extra energy being stored in the atmosphere is being “expressed in stronger winds…in stronger rainfall.”  How else would it be possible to explain the catastrophic natural phenomenon occurring the last few years?

This is where the Cause Mapping process can help focus all parties on solving the problem, instead of arguing or blaming.  The first step in the process is to define the issue by its impact to overall goals.  In this case, all parties can agree that the destruction and loss of life are the principle impacts.

The next step is to analyze the causes in a visual map.  A simple Cause Map can lay the foundation for a more detailed analysis, so a 5-Why map is usually the best starting point.  From there more causes can be added to the map; all possibilities should be included on the first draft.  When all possible causes are included, it focuses on team on brainstorming instead of debating.

Let’s take a closer look at why so many tornados have hit densely populated areas.  There are primary four reasons identified in the Cause Map.  First, there have been more tornados.  This could be because more are being counted, due to better weather tracking capabilities, or because there simply are more occurring.  Second, there are more forceful tornados than usual.  This could be related to more supercell thunderstorms, since most tornados spring from these types of weather systems.  Because this isn’t known for sure, a question mark indicates that more evidence is needed to support or disprove this hypothesis.  Likewise, it’s possible more strong weather systems are being caused by global warming.

Instead of stopping the analysis to debate global warming, it’s most productive to continue exploring why tornados are touching down in population centers.  It’s not simply a function of the tornados.  There also happen to be more people near where tornados are, and there are more structures which are susceptible to tornado damage.

More people are near where the tornados are because there are more people.  While this is straightforward, it’s often overlooked in the debate and is precisely a reason why more people would perish in a tornado.  People might also be in the area because they have little time to evacuate or take appropriate shelter, unlike in a hurricane.  Advance warning averages just 11 minutes.

Despite many advances in Doppler radar technology and satellite data, tornados are still generally detected the old fashioned way.  Today, a web of 290,000 trained volunteers, called SKYWARN, provide severe weather alert information to the National Weather Service.  Since its inception in the 1970s, SKYWARN has helped the NWS to issue more timely and accurate severe weather warnings.  The NOAA’s National Severe Storms Lab is looking to improve that advanced warning time to 20 minutes, so this might be a possible solution to reducing the number of deaths and injuries caused by tornados.

The fourth factor is that people tend to be located in buildings which are highly susceptible to tornado damage.  More Americans are living in manufactured or modular homes than in previous decades.  As of 2009, there were 8.7 million mobile homes in the United States.  Mobile homes account for nearly half of tornado fatalities.  When other factors are normalized, the data shows unequivocally that mobile homes are more likely to sustain catastrophic damage during tornados.  Some states have begun to take steps to improve the building codes for such dwellings and also to require hardened shelters at mobile home sites.

As even this fairly simple Cause Map demonstrates, there are many factors contributing to this season’s frightening weather.  Focusing on a single cause can mask the many reasons required to produce an effect, and in the end only limits productive debate.

Root Cause Analysis - Incident Investigation

The Side Effects of Fracking: Explosive Water?

By ThinkReliability Staff

America’s push for clean energy has certainly been a source of intense debate – the safety of off-shore drilling, the hidden costs of ethanol subsidies, even the aesthetics of wind farms.  New evidence is set to increase the intensity on yet another topic – the debate over hydraulic fracturing.

Hydraulic fracturing is a process where internal fluid pressure is used to extend cracks, or fractures, into a rock formation.  It can occur in nature, but in man-made operations fractures are made deep in the earth by pumping fluid (mostly water) and a proppant (such as sand) out the bottom of a well.  The proppant prevents the fracture from closing back up after the injection of fluid stops.  Chemicals are sometimes added to the pumping fluid to aid in the process.  These fractures allow the gas or liquid trapped in the rock formation to flow back through the fracture, up the well and out for production.

More commonly known as “fracking”, the technique is used to release natural gas from shale rock formations.  These formations, especially common on the East Coast and in Canada, have provided thousands of new, well-paying jobs.  Fracking has allowed natural gas companies to access enormous reserves of natural gas, previously thought inaccessible and prohibitively expensive to drill.  In fact fracking has allowed drillers to tap what is potentially the world’s largest known reserve of natural gas in the Marcellus and Utica shale deposits, stretching from New York to Georgia.

As with any new technology however, there are potential consequences.  Lawmakers and regulators have debated the safety of the largely unregulated fracking industry, but with little definitive evidence either way…until now.  A study by Duke University has concluded that fracking does indeed lead to methane contamination in drinking water.  Methane is the primary component in natural gas and is not lethal to consume.  However, high concentrations are explosive.

The study determined that fracking causes methane to leak into drinking water.  Water sources within a kilometer were found to have significant levels of methane, more than 17 times higher than wells located further from drilling sites.  Furthermore, it was determined that the source of the methane was the much older methane released from the bedrock, versus newer methane produced naturally in the environment.

The exact reason for this is unclear, but a Cause Map can lay out the possible areas needing further investigation.  For instance, the frack chemicals might enter the water supply accidentally during the drilling process.  Spills could also contaminate surface water, or chemicals could migrate into the water supply.

The study indicates that chemical migration is most likely what’s happening.  Surface spills, which have happened, are not a major contributor to the wide-spread methane contamination; so that cause can be left in the Cause Map but won’t be investigated further for our purposes.  Furthermore, the study produced no evidence that the drilling process itself was causing the contamination; so that block can be crossed off the Cause Map.

That leaves one possibility – migration.  The chemicals (including methane) could migrate in two different ways – through the well casing or through the bedrock.  The study’s authors felt it was unlikely that chemicals were migrating thousands of feet through bedrock, so migration from well casings experiencing high pressure flow  is more probable.  While more evidence is needed, it is possible that the well casings are weakened by the fracking process which pushes sand through the casings at high pressure.

An EPA study looks to definitively determine fracking’s impact on drinking water, and specifically human health.  However that study is not scheduled to be completed until 2014.  Until then, lawsuits and tighter regulations are likely to dominate headlines.

Root Cause Analysis - Incident Investigation

Grounding the 737’s: SWA Flight 812

By ThinkReliability Staff

As new information comes to light, processes need to be reevaluated.  A hole in the fuselage of a 15-year-old Boeing 737-300 led to the emergency descent of Southwest Airlines Flight 812.  737’s have been grounded as federal investigators determine why the hole appeared.  At the moment, consensus is that a lap joint supporting the top of the fuselage cracked.

While the investigation is still in the early stages, it appears that stress fatigue caused a lap joint to fail.  Stress fatigue is a well known phenomenon, caused in aircraft by the constant pressurization and depressurization occurring during takeoff and landing.  Mechanical engineers designing the aircraft would have been well aware of this phenomenon.  The S-N curve, which plots a metal’s expected lifespan vs. stress, has been used for well over a century.

Just as a car needs preventative maintenance, planes are inspected regularly for parts that are ready to fail.  However, the crack in lap joint wasn’t detected during routine maintenance.  In fact, that joint wasn’t even checked.  It wasn’t an oversight however.  Often the design engineers also set the maintenance schedule, because they hold the expertise needed to determine a reasonable procedure.  The engineers didn’t expect the part to fail for at least 20,000 more flight hours.  At the moment, it’s unclear why that is.

In response to the incident, the FAA has grounded all similar aircraft and ordered inspections of flights nearing 30,000 flight hours.   Cracks have been found in 5 aircraft of 80 grounded aircraft so far.  However a looming concern is how to deal with 737’s not based in the United States, and therefore outside the FAA’s jurisdiction.

Root Cause Analysis - Incident Investigation

San Francisco’s Stinking Sewers

By ThinkReliability Staff

The Golden Gate City is well known for its ground-breaking, environmentally-friendly initiatives.  In 2007 San Francisco outlawed the use of plastic bags at major grocery stores.  The city also mandated compulsory recycling and composting programs in 2009.  Both ordinances were the first laws of their kind in the nation, and criticized by some for being overly aggressive.  Likewise San Francisco’s latest initiative, to reduce city water usage by encouraging the use of low-flow toilets, has faced harsh criticism.

Recently San Francisco began offering substantial rebates to homeowners and businesses to install high efficiency toilets (HETs).  These types of toilet use 1.28 gallons or less per flush, down from the 1.6 gpf versions required today by federal law and even older 3.4 gpf toilets from decades ago.  That means that an average home user will save between 3,800 to 5,000 gallons of water per year per person.  In dollars, that’s a savings of $90 annually for a family of four.  This can quickly justify the cost of a new commode, since a toilet is expected to last 20 years.

Aside from cost savings, there are obvious environmental benefits to reduced water use.  The city initially undertook the HET rebate initiative to decrease the amount of water used overall by the city and the amount of wastewater requiring treatment.  They were successful, and water usage decreased.  In fact, the city’s Public Utilities Commission stated that San Francisco residents reduced their water consumption by 20 million gallons of water last year.  San Francisco last year used approximately 215 million gallons per day.  This also met other goals the city had, such as reducing costs to consumers.  Unintentionally though, the HET rebate initiative impacted a different goal – Customer Service.

As shown on the associated Cause Map, reduced water flow had a series of other effects.  While water consumption – and presumably waste water disposal – shrank significantly, waste production has remained constant.  Despite $100M in sewage systems upgrades over the past five years, current water flow rates are not high enough to keep things moving through the system.  As a result sewage sludge builds up in sewer lines.  As bacteria eat away at the organic matter in the sludge, hydrogen sulfide is released.  Hydrogen sulfide is known for its characteristic “rotten egg” smell.

This creates an unfortunate situation.  No one wants to walk through smelly streets.  Further, slow sewage means a build-up of potential harmful bacteria.  However, everyone agrees San Francisco should strive to conserve water.  Water is a scarce and increasingly expensive resource in California.  What’s the next step in solving the stinking sewer problem?

San Francisco is not the first city to deal with this issue.  There is substantial debate over the city’s current plan to purchase $14M in bleach to clean up the smell.   Many parties are concerned about potential environmental impacts and potential contamination to drinking water.  Other solutions have been proposed by environmental activists, but may have financial ramifications.

Cause Maps can help all parties come to agreement because they focus problem solvers on the goals, not the details of the problem.  In this case, all parties are trying to protect the environment and reduce costs to city residents.  Based on those goals and the Cause Map, potential solutions have been developed and placed with their corresponding causes.  The next step is to proactively consider how these new actions might affect the stakeholders’ goals.  Perhaps other goals could be impacted, such as the safety of drinking water and potential contamination of San Francisco Bay.  Financial goals will surely be impacted to varying degrees with each solution.  Revising the Cause Map can help identify the pros and cons of each approach and narrow down which solution best satisfies all parties.