Tag Archives: accident

Root Cause Analysis - Incident Investigation

Dissecting Safety Incidents: Using root cause analysis to reveal culture issues

By ThinkReliability Staff

The objective of a root cause analysis investigation is to prevention.  The causes of an incident are investigated, so that solutions can be developed and implemented, to reduce the risk of the same or a similar problem from occurring.  The process sounds easy, but in practice it can become more involved.  For example, what do you do when one of the identified causes is “lack of safety culture”?  How exactly do you solve that?

This is the issue that the Washington DC Metrorail (Metro) is currently facing.  The National Transportation and Safety Board (NSTB) recently released findings from the investigation of a DC metro train crash that killed nine last June.  (See our previous blog for more details). Predictably, the NSTB findings include several technical issues including failed track circuits and lack of adequate testing, but the list of causes also includes items like lack of safety culture and ineffective oversight.

Fortunately, the NSTB also provided recommendations such as developing a non-punitive safety reporting program, establishment of periodic inspections and maintenance procedures for the equipment that failed during this accident, and reviewing the process used to pass along safety and technical information.  One of the important things to notice in this example is that the recommendations are fairly specific, even if the stated cause is a little vague.  Specific solutions are necessary if they are going to be effectively implemented.

If you find yourself at a point in your organization where a cause is identified as “lack of safety culture”, it’s a good idea to keep asking why questions until you identify the specific problems that are causing the issue.  Is it the safety information that is lacking or incorrect?  Is the process that provides the information confusing?  Do the workers need better safety equipment?  Knowing all the details involved will allow better solutions to be developed.  And better solutions result in lower risks in the future.  Culture is the shared values and practices of the people in an organization.  The Cause Mapping method of root cause analysis has an effective way for an organization to identify “culture gaps” by thoroughly dissecting just one of its incidents.

Root Cause Analysis - Incident Investigation

Death of Luger at 2010 Winter Olympics

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By Kim Smiley

On February 12, 2010, Nodar Kumaritashvili, an Olympic luger from the country of Georgia, was killed during a practice run.  He lost control of his sled, flew off the track and hit a steel pole.

The investigation into the accident is still ongoing, but a root cause analysis can be started with the information that is available.  This accident obviously impacts the safety goal because an athletic was killed and it also had potential to impact the schedule goal because the track was closed during the initial investigation.

There are a number of causes that can be added to the Cause Map.  One of the more obvious causes for the accident is that the athletic was traveling at high speeds.  This occurred because the crash happened near the bottom of the track so the sled was near its top speed.  Additionally, the Vancouver Olympic track is also a particularly fast track.  Top speeds on the track were predicted to be 96 mph, nearly 6 miles faster than the standing 2000 world speed record.

How did the track get designed to be so much faster than typical tracks?  There are a number of causes that contributed to fast design.  The designers choose Whistler as the site of the track because Whistler has a colder climate than the alternatives, resulting in firm, fast ice and because there is high tourist traffic there that would help make the track a commercial success after the Olympics.  Whistler was also the site of the Olympic alpine events.

The land that was available at Whistler was long and narrow.  The site was a valley approximately 100 yards by 800 yards.  By comparison, the Calgary track was about 300 yards wide and Salt Lake City’s track was 500 yards.  Designing a track to fit in the available region meant the track couldn’t include any long curves that slow down speed as is typical.

The result was the fastest track in the history of the sport.

As the investigation continues, more details become available and they can be added to the Cause Map.

In order to ensure safety during the Olympic Games, several solutions were implemented following the accident. A wooden wall was added to the curve where the accident occurred to keep athletics on the track, the steel poles were padded and events were started lower on the track to limit the maximum speed.  The lower start was predicted to slow top speeds in the men’s events by about 5 mph.

There have been several crashes on the course since the accident, but thankfully no farther significant injuries have occurred.

Root Cause Analysis - Incident Investigation

Metro Train Derailment Washington D.C.

By ThinkReliability Staff

On February 12, 2010 at approximately 10:13 A.M., a six-car Red Line Metro train taking passengers to Shady Grove derailed near the Farragut North station in Washington, D.C.  If you’ve been reading our blog, you’ve seen our reports on three previous Metro incidents in the past year (two Metro workers were killed in January, two trains collided last November, and two trains also collided last June).

Thankfully, this derailment caused only minor injuries.  However, it did result in an extremely messy commute for a lot of people, due to a severe delay in train service.  Additionally, there was likely damage to the train and/or track, which will require labor to repair.  More labor will be required for the investigation.

All the basic information, as well as the impacts to the goals (the injuries, delay in service, property damage and labor required as a result of the incident), relating to this event are captured in a problem outline.  We can also capture anything that was different at the time.  Here we note that there were major storms in the area and that the commute was especially heavy.

Once we have completed the outline, we can begin the Cause Map with the goals that were impacted.  The impacts to the goals resulted from the train derailing.  The train derailed when the front wheels slipped and the lead car came off the track.  Metro and National Transportation Safety Board (NTSB) investigators are determining the causes of the derailment, but some of the things that will be looked at as causes include: the train was moving onto a pocket track.  Other trains previously have slipped off the track while moving onto a pocket track (a side track that allows trains to pass other trains or move around construction).  It’s unclear whether the train was moving onto the pocket track to move around other trains or track work.

As previously mentioned, the snow and icy conditions (which have been extreme as of late in D.C.) may have caused the tracks to be slippery, which potentially contributed to the derailment.  It’s possible there was damage to the tracks or switch, as the area where the derailment took place is the oldest portion of the Red Line, and is due for maintenance.  Because of an extreme budget shortfall on the Metro line, repairs to tracks and cars have been delayed.  Last but not least, there’s a possibility that the weight of the rail car may have been a factor in the derailment.  The cars were extremely crowded because of an insufficient number for the commute.  Metro was not running the normal number of cars because it had not completely recovered from the storm, but there were the normal number of commuters because the Federal Government was open.  (The Federal Government usually remains closed when the Metro system is unable to run at full capacity.)

Even though we are not yet certain which factors may have contributed to the derailment, we can include them all on the Cause Map until we are able to rule some of them out.  Even more detail can be added to this Cause Map as the analysis continues. As with any investigation the level of detail in the analysis is based on the impact of the incident on the organization’s overall goals.  View the beginning stage of the root cause analysis investigation by clicking on “Download PDF” above.

Root Cause Analysis - Incident Investigation

Toyota Recall: Problems, Interim Solutions and Permanent Solutions

by Kim Smiley

On September 29, 2009, Toyota/Lexus issued a safety advisory that some 2004-2010 model year vehicles could be prone to a rapid acceleration issue if the floor mat moved out of place and jammed the accelerator pedal. Although the recall is only applicable in the U.S. and Canada because of the type of floor mats used, over 4 million vehicles are affected by the recall.

Although all the solutions to this problem have not yet been implemented, we can look at the issue so far in a Cause Map, or visual root cause analysis. First we define the problem. Here we could consider the problem the recall, or the acceleration problems. We can list all the models and years that are affected by the recall, and that the recall is limited to the U.S. and Canada.

We define the problem with respect to the organization’s goals. There have been at least 5 fatalities addressed by the National Highway Transportation Safety Administration (NHTSA), though some media outlets have reported more. Additionally, the NHTSA has reported 17 accidents (again, some claim more) and has received at least 100 complaints. The fatalities and accidents are impacts to the safety goal. Complaints are impacts to the customer service goal. The recall of more than 4 million cars is an impact to the production/schedule goal, and the replacement of the accelerator pedals and floor mats as a result of the recall is estimated to cost $250 million, which is an impact to the property goal.

Once we’ve completed the outline, we can begin the Cause Map, or the analysis step of the process. The fatalities are caused by vehicle crashes resulting from a loss of control of the vehicle. The loss of control is caused by a sudden surge of acceleration, inability to brake, and sometimes an inability to shut down the engine of the car. Toyota says the sudden bursts of acceleration are caused by entrapment of the accelerator pedal due to interference from floor mats. Toyota refutes the possibility that there may be a malfunction in the electronic control system, saying it’s been ruled out by Toyota research.

The vehicles are unable to brake because the brake is non-functional when the accelerator pedal is engaged, as it is in these cases. Additionally, owners whose models are equipped with keyless ignition cannot quickly turn off their ignition. These models require the ignition button to be pressed for 3 seconds to prevent inadvertent engine stops, and the instructions are not posted on the dashboard, so owners who weren’t meticulous about reading (or remembering) instructions from the owners’ manual may not know how to turn off the car while moving at very quick speeds.

When the Cause Map is complete to a sufficient level of detail, it’s time to explore some solutions. In this case, the permanent solutions (which will reduce the risk of these accidents most significantly) to be implemented by Toyota are to reconfigure the accelerator pedal, replace the floor mats, and install a brake override system which will allow the brakes to function even with the accelerator pedal engaged. However, designing and implementing these changes for more than 4 million cars will take some time, so owners of Toyotas require interim solutions. Interim solutions are those that do not sufficiently reduce the risk for long-term applicability but can be used as a stop-gap until permanent solutions are put in place. In this case, Toyota has asked owners to remove floor mats, and has put out guidance that drivers who are in an uncontrolled acceleration situation should shift the engine into neutral, which will disengage the engine and allow the brake to stop the car.

View the high level summary of the investigation by clicking “Download PDF” above.

Learn more about the recall at the NHTSA website.