Tag Archives: marine

Root Cause Analysis - Incident Investigation

8 Injured by Arresting Cable Failure on Aircraft Carrier

By ThinkReliability Staff

An aircraft carrier is a pretty amazing thing. Essentially, it can launch planes from anywhere. But even though aircraft carriers are huge, they aren’t big enough for planes to take off or land in a normal method. The USS Dwight D. Eisenhower (CVN 69) has about 500′ for landing planes. In order for planes to be able to successfully land in that distance, it is equipped with an arresting wire system, which can stop a 54,000 lb. aircraft travelling 150 miles per hour in only two seconds and a 315′ landing area. This system consists of 4 arresting cables, which are made of wire rope coiled around hemp. These ropes are very thick and heavy and cause a significant risk to personnel safety if they are parted or detached.

This is what happened on March 18, 2016 while attempting to land an E-2C Hawkeye. An arresting cable came unhooked from the port side of the ship and struck a group of sailors on deck. At least 8 were injured, several of whom had to be airlifted off the ship for treatment. We will examine the details of this incident within a Cause Map, a visual form of root cause analysis.

The first step in any problem investigation is to define the problem. We capture the what, when, and where within a problem outline. Additionally, we capture the impacts to the goals. The injuries as well as the potential for death or even more serious injuries are impacts to the safety goal. Flight operations were shut down for two days, impacting both the mission and production/ schedule goal. The potential of the loss of or (serious damage to) the plane is an impact to the property goal. (In a testament to the skill of Navy pilots, the plane returned to Naval Station Norfolk without any crew injuries to the flight crew or significant damage to the plane.) The response and investigation are an impact to the labor goal. It’s also useful to capture the frequency of these types of incidents.   The Virginian-Pilot reports that there have been three arresting-gear related deaths and 12 major injuries since 1980.

The next step in the problem-solving process is to determine the cause-and-effect relationships that led to the impacted goals. Beginning with the safety goal, the injuries to the sailors resulted from being struck by an arresting cable. When a workplace injury results, it’s also important to capture the personal protective equipment (PPE) that may have impacted the magnitude of the injuries. In this case, all affected sailors were wearing appropriate PPE, including heavy-duty helmets, eye and ear protection. This is a cause of the injuries because had they NOT been wearing PPE, the injuries would have certainly been much more severe, or resulted in death.

The arresting cable struck the sailors because it came unhooked from the port side of the ship. The causes for the detachment of the cable have not been conclusively determined; however, a material failure results from a force on the material that is greater than the strength of the material. In this case the force on the arresting cable is from the landing plane. In this case, the pilot reported the plane “hit the cable all at once”, which could have provided more force than is typical. The strength of the cable and connection may have been impacted by age or use. However, arresting cables are designed to “catch” and slow planes at full power and are only used for a specific number of landings before being replaced.

Other impacted goals can be added to the Cause Map where appropriate (additional relationships may result). In this case, the potential damage to the plane resulted from the landing failure, which was caused by the detachment of the arresting cable AND because the arresting cable is needed to safely land a plane on an aircraft carrier.

The last step of the Cause Mapping process is to determine solutions to reduce the risk of the incident recurring. More investigation is needed to ensure that the cable and connection were correctly installed and maintained. If it is determined that there were issues with the connection and cable, the processes that lead to the errors will be improved. However, it is determined that the cable and connection met design criteria and the detachment resulted from the plane landing at an unusual angle, there may be no changes as a result of this investigation.

It seems unusual that an investigation that resulted in 8 injuries would result in no action items. However, solutions are based on achieving an appropriate level of risk. The acceptable level of risk in the military is necessarily higher than it is in most civilian workplaces in order to achieve desired missions. Returning to the frequency from the outline, these types of incidents are extremely rare. The US Navy currently has ten operational aircraft carrier (and an eleventh is on the way). These carriers launch thousands of planes each year yet over the last 36 years, there have been only 3 deaths and twelve major injuries associated with landing gear failures, performing a dangerous task in a dangerous environment. Additionally, in this case, PPE was successful in ensuring that all sailors survived and limiting injury to them.

To view the outline and Cause Map of this event, click on “Download PDF” above.

 

Uncategorized

Oil Leaked from shipwreck near Newfoundland

By Kim Smiley

On March 31, 2013, oil was reported in Notre Dame Bay, Newfoundland.  Officials traced the source of the oil back to a ship, the Manolis L, that sank in 1985 after running aground.  The Manolis L is estimated to have contained up to 462 tons of fuel and 60 tons of diesel when it sank and much of that oil is believed to still be contained within the vessel.  Officials are working to ensure the oil remains contained, but residents of nearby communities who rely on tourism and fishing are concerned about the potential for more oil to be released into the environment.

A Cause Map, a visual format for performing root cause analysis, can be built to better understand this issue.  There are three steps in the Cause Mapping process. The first step is to fill out an Outline with the basic background information along with listing how the problem impacts the goals.  There is also space on the Outline to note the frequency of the issue.  For this example, 2013 was the first time oil was reported to be leaking from this particular sunken ship, but there have been 700 at-risk sunken vessels identified in Canadian waters alone.  It’s worth noting this fact because the amount of resources a group is willing to use to address a problem may well depend on how often it is expected to occur.  One leaking sunken ship is a different problem than potentially having hundreds that may require action.

The second step is to perform the analysis by building the Cause Map.  A Cause Map is built by asking “why” questions and laying out the answers to visually show the cause-and-effect relationships.  Once the causes have been identified, the final step is to develop and implement solutions to reduce the risk of similar problems occurring in the future.  Click on “Download PDF” to view an Outline and intermediate level Cause Map for this problem.

In this case, the environmental goal is clearly impacted because oil was released into the environment.  Why? Oil leaked out of a sunken ship because a ship had sunk that contained a large quantity of oil and there were cracks in the hull.  The hull of this particular ship is thin by modern standards (only a half-inch) and it has been sitting in sea water for the last 30 years.  A large storm hit the region right before oil was first reported and it is believed that the hull (already potentially weakened by corrosion) was damaged during the storm.  The Coast Guard identified two large cracks in the ship that were leaking oil during their investigation.

Once the causes of the issue have been identified, the final step is to implement solutions to reduce the risk of future problem.  This is where a lot of investigations get tricky.  It is often easier to identify the problem than to actually solve it. It can be difficult to determine what level of risk is acceptable and how many resources should be allotted to an issue.  The cracks in the hull of the Manolis L have been patched using weighted neoprene sealants and a cofferdam has been installed to catch any oil that leaks out.  The vessel is being monitored by the Canadian Coast Guard via regular site visits and aerial surveillance flights. But the oil remains in the vessel so there is the potential that it could be released into the environment.

Many local residents are fighting for the oil to be removed from the sunken ship, rather than just contained, to further reduce the risk of oil being released into the environment. But removing oil from a sunken ship is very expensive.  In 2013, it cost the Canadian Coast Guard about $50 million to remove oil from a sunken ship off the coast of British Columbia. So far, officials feel that the measures in place are adequate and that the risk doesn’t justify the cost of removing the oil from the vessel. If they are right, the oil will stay safely contained at a fraction of the cost of removing it, but if they are wrong there could be lasting damage to local communities and wildlife.

In situations like this, there are no easy answers.  Anybody who works to reduce risk faces similar tradeoffs and generally the best you can do is to understand a problem as thoroughly as possible to make an informed decision about the best use of resources.

Root Cause Analysis - Incident Investigation

Newly Commissioned USS Milwaukee Breaks Down at Sea

By ThinkReliability Staff

On December 11, 2015, just 20 days after commissioning, the USS Milwaukee completely lost propulsion and had to be towed back to port. This obviously brought up major concerns about the reliability of the ship. Said Senator John McCain (R-Arizona), head of Senate’s Armed Services Committee, “Reporting of a complete loss of propulsion on USS Milwaukee (LCS 5) is deeply alarming, particularly given this ship was commissioned just 20 days ago. U.S. Navy ships are built with redundant systems to enable continued operation in the event of an engineering casualty, which makes this incident very concerning. I expect the Navy to conduct a thorough investigation into the root causes of this failure, hold individuals accountable as appropriate, and keep the Senate Armed Services Committee informed.”

While very little data has been released, we can begin an investigation with the information that is known. The first step of a problem investigation is to define the problem. The “what, when and where” are captured in a problem outline, along with the impacts to the organization’s goals. In this case, the mission goal is impacted due to the complete loss of propulsion of the ship. The schedule/production goal is impacted by the time the ship will spend in the shipyard receiving repairs. (The magnitude and cost of the repairs has not yet been determined.) The property/equipment goal is impacted because metal filings were found throughout both the port and starboard engine systems. Lastly, the labor and time goal is impacted by the need for an investigation and repairs.

The next step of a problem investigation is the analysis. We will perform a visual root cause analysis, or Cause Map. The Cause Map begins with an impacted goal and asking “why” questions to diagram the cause-and-effect relationships that led to the incident. In this case the complete loss of propulsion was caused by the loss of use of the port shaft AND the loss of use of the starboard shaft. The ship has two separate propulsion systems, so in order for the ship to completely lose propulsion, the use of both shafts had to be lost. Because both causes were required, they are joined with an “AND”.

We continue the analysis by continuing to ask “why” questions of each branch. The loss of use of the port shaft occurred when it was locked as a precaution because of an alarm (the exact nature of the alarm was not released). Metal filings were found in the lube oil filter by engineers, though the cause is not known. We will end this line of questioning with a “?” for now, but determining how the metal filings got into the propulsion system will be a primary focus of the investigation. The loss of use of the starboard shaft occurred due to lost lube oil pressure in the combining gear. Metal filings were also found in the starboard lube oil filter. Again, it’s not clear how they got there, but it will be important to determine how the lube oil system of a basically brand new ship was able to obtain a level of contamination that necessitated full system shutdown.

While metal filings in the lube oil system is not a class-wide issue, it’s not the first time this class of ship has had problems. The USS Independence and USS Freedom, the first two ships of the class, suffered galvanic corrosion which caused a crack in the Freedom’s hull. The Freedom also suffered issues with its ship service diesel engines, a corroded cable, and a faulty air compressor.

Once all the causes of the breakdown are determined, engineers will have to determine solutions that will allow the ship to return to full capacity. Additionally, because of the number of problems with the class, the investigation will need to take a good look at the class design and manufacturing practices to see if there are issues that could impact the rest of the class going forward.

To view a one-page downloadable PDF with the beginning investigation, including the problem outline, analysis, and timeline, click “Download PDF” above.

Root Cause Analysis - Incident Investigation

Houston Ship Channel Closed After Ships Collide

By Kim Smiley

On March 9, 2015, two large ships collided in the Houston Ship Channel, one of the busiest waterways in the United States.  There were no major injuries reported, but the accident resulted in the release of methyl tertiary-butyl ether, commonly called MTBE, a chemical that is used as a fuel additive.  The clean-up and investigation of the collision closed the channel from the afternoon of March 9 until the morning of March 12.

At the time of the collision, the tanker Carla Maersk was traveling outbound in the channel transporting MTBE.  The bulk carrier Conti Perido was heading inbound with a load of steel.  Both ships were significantly damaged by the collision and three cargo tanks ruptured on the Carla Maersk, spilling the MTBE. Limited information has been released about what caused the accident, but a National Transportation Safety Board investigation is underway.  Initial reports are that both vessels were traveling at about 9 knots, which is typical for this stretch so excessive speed does not appear to be a cause.  It has also been reported that it was foggy at the time of the accident which may have played a role in the accident.

An initial Cause Map can be built using the information that is available.  The first step in the Cause Mapping process is to fill in an Outline with the basic background information along with the impacts to the goals.  Like many incidents, this collision impacted several different goals.  The safety goal was impacted because MTBE is toxic and has the potential to cause injuries.  The environmental goal was clearly impacted by the release of MTBE.  The multiple-day closure of the Houston Ship Channel is an impact to the production/schedule goal and the impact to local businesses resulting from closure is an impact to the economic goal.  The damage to the ships is an impact to the equipment goal.

On the outline, there is also a line to record the frequency of how often a similar event has occurred.  It’s important to consider the frequency because a small problem that occurs often may very well warrant a more detailed investigation than a small problem that has only been seen once.  In this example, there have been previous ship collisions.  This accident was the second ship collision to occur in the channel in a week.  Two large ships bumped on March 5, 2015, which did not result in any injuries or pollution.

Release of MTBE is a significant concern, but the impacts of this ship collision could easily have been worse.  MTBE is volatile and flammable so there could have been a fire or the ships could have been carrying something more dangerous.  It may be difficult to get the data, but it would be interesting to know how many near misses have occurred between ships traveling in the channel. The frequency that accidents are occurring needs to be considered along with the details of any individual incident when conducting an investigation. Two collisions in a week is a pretty clear indication that there is potential for more to occur in the future if nothing is changed.

Root Cause Analysis - Incident Investigation

Hundreds Saved by Arduous Helicopter Rescue From Ferry Fire

By Kim Smiley

In a grueling rescue effort, 427 people were saved from a passenger ferry, Norman Atlantic, which caught fire December 28, 2014 off the coast of Greece.  About 150 people managed to escape the fire in lifeboats, but the remaining passengers were lifted to safety via helicopter.  Gale force winds, heavy rain and darkness all combined to make a difficult rescue operation even more daunting. Ten people died as a result of the accident with few details known about what caused the fatalities.

A Cause Map, a visual root cause analysis, can be built to analyze this incident.  The investigation is just beginning and there are still many unknowns, but an initial Cause Map can be begun that can easily be expanded to incorporate new information as it becomes available.  Even the exact number of people onboard has been difficult to determine because there were several stowaways discovered during the rescue operations that weren’t listed on the ship’s manifest.

What is known is that the fire began early in the morning of December 28th and 427 people were rescued off the ferry. Early reports are that the fire started on the parking deck where there were tanker trucks filled with oil.  Witness accounts indicate that the fire spread fairly quickly, leading to speculation that the fire doors failed.  As the fire progressed, the ship lost power.  Once power was gone, the lifeboats were useless because they require electricity to be lowered.  The heat from the fire drove passengers to the top deck and bridge where they were bombarded by cold, rain and thick smoke for many miserable and likely terrifying hours.  Helicopters pulled passengers to safety one by one, working through the windy night with night vision goggles.

In a stark contrast to the South Korea ferry that capsized off Byungpoong in April, the captain was the last person to leave the Norman Atlantic. The rescue effort was truly impressive.  As Greek Prime Minister Antonis Samaras said, the “massive and unprecedented operation saved the lives of hundreds of passengers following the fire on the ship in the Adriatic Sea under the most difficult circumstances.”

The Italian Transport Ministry has seized the vessel pending an investigation into the fire and thorough inspection of the ship.  Whenever a disaster of this magnitude occurs, it is worth understanding exactly what happened and reviewing what could be done better in the future.  There will be many lessons to learn from this incident, both in how to prevent and fight shipboard fires and how to perform helicopter rescues at sea.

To view a high level Cause Map of this incident, click on “Download PDF” above.

Root Cause Analysis - Incident Investigation

Extensive Fire on USS George Washington Placed Crew at Risk

By ThinkReliability Staff

When fire broke out in 2008 on aircraft carrier USS George Washington in an unmanned space that was being used to improperly store flammable materials, it took more than 8 hours to find the source of, and extinguish, the fire. In the Navy’s investigation report, Admiral Robert F. Willard, commander of the US Pacific Fleet, stated “It is apparent from this extensive study that there were numerous processes and procedures related to fire prevention and readiness and training that were not properly functioning. The extent of damage could have been reduced had numerous longstanding firefighting and firefighting management deficiencies been corrected.”

The processes and procedures that were implicated in the investigation of the fire can be examined in a Cause Map, or a visual root cause analysis. This process begins by identifying the goals impacted. In this case, the primary goal impacted was the safety goal. Thirty-seven sailors were injured; one was seriously burned. There were no fatalities. In addition, the damage to the ship was estimated at $70 million and left the ship unusable for 3 months.

Beginning with the impacted safety goal, asking ‘Why’ questions allows us to develop the cause-and-effect relationships that led to those impacted goals. In this case, the injuries to sailors resulted from the extensive fire aboard ship. In addition, some of the affected sailors (including the sailor who was seriously burned) did not have adequate protective clothing. Specifically, liners worn underneath firefighting gear were not available in one repair locker because they were being laundered. Both the fire and the inadequate protective gear were causally related to the injuries so they are both included on the Cause Map and joined with ‘and’.

Asking additional ‘why’ questions adds more detail to the Cause Map. When investigating a fire, it’s important to include the factors that resulted in the initiation of the fire (heat, fuel and oxygen) as well as those that allowed the fire to spread. In this case, the ignition (or heat) source was believed to be a cigarette butt. On-scene evidence showed that smoking was occurring in the area, against regulation. The ship was found to have inadequate training regarding the smoking policy and inadequate control over the locations where smoking was occurring, because regular zone inspections were not being held.

The initial fuel source was determined to be refrigerant oil and other flammable materials improperly stored in an unmanned space where the fire began. The oil was not turned in as required by procedure over a concern about the difficulty of retrieving it. Because the oil was never entered into the inventory control system, the storage discrepancy was not noted. The unmanned space in which it was stored was not inspected. Unmanned spaces were not included in zone inspections and the area had not been designed as a tank or void to be identified in the void and tank inspection.

Once a fire breaks out, the speed in which the source is found and extinguished has the most impact on the safety of personnel. In this case, the source of the fire was not found for eight hours.   Not only did the fire begin in an unmanned area, the drawings showing the layout of the ship were inaccurate, because the ship was in the midst of alterations.

Developing the causes the resulted in the impacted goals allows for identification of all the processes and procedures that need to be re-examined to reduce risk of recurrence. In this case, the report identified multiple processes and procedures that were re-evaluated in the wake of the disaster, including those for hazardous material storage, training, inspection and firefighting.

To learn more, click here to read the Navy investigation report. To view a one-page overview of the Outline and Cause Map, please click on “Download PDF” above.

Root Cause Analysis - Incident Investigation

The Salvage Process of Costa Concordia

By ThinkReliability Staff

On September 16, 2013, the fatally stricken Costa Concordia was lifted upright (known as “parbuckling”) after salvage operations that were the most expensive and involved the largest ship ever. The ship ran aground off the coast of Italy January 13, 2012 (see our previous blog about the causes of the ship running aground) and has been lying on its side for the 20 months since.

The ship grounding had immediate, catastrophic impacts, including the death of 32 people. However, it also had longer term impacts, mainly pollution from the fuel, sewage and other hazardous materials stored aboard the ship. It was determined that the best way to minimize the leakage from the ship would be to return it upright and tow it to port, where it the onboard waste could be emptied and disposed of, then the ship broken up for scrap.

Because a salvage operation of this magnitude (due to the size and location of the ship) had never been attempted, careful planning was necessary. Processes like this salvage operation can be described in a Process Map, which visually diagrams the steps that need to be taken for a process to be completed successfully. A Process Map differs from a Cause Map, which visually diagrams cause-and-effect relationships to show the causes that led to the impacts (such as the deaths and pollution). Whereas a Cause Map reads backwards in time (the impacted goals result from the causes, which generally must precede those impacts), a Process Map reads from left to right along with time. (Step 1 is to the left of, and must be performed before, Step 2.) In both cases, arrows indicate the direction of time.

Like a Cause Map, Process Maps can be built in varying levels of detail. In a complex process, many individual steps will consist of more detailed steps. Both a high level overview of a process, as a well as a more detailed breakdown, can be useful when developing a process. Processes can be used as part of the analysis step of an incident investigation – to show which steps in a process did not go well – or as part of the solutions – to show how a process developed as a solution should be implemented.

In the example of the salvaging of the Costa Concordia, we use the Process Map for the latter. The salvaging process is part of the solutions – how to remove the ship while minimizing further damage and pollution. This task was not easy – uprighting the ship (only the first step in the salvage process) took 19 hours, involved 500 crewmembers from 26 countries and cost nearly $800 million. Other options used for similar situations included blowing up the ship or taking it apart on-site. Because of the hazardous substances onboard – and the belief that two bodies are still trapped under or inside the ship – these options were considered unacceptable.

Instead, a detailed plan was developed to prepare for leakage with oil booms that held sponges and skirts, then installed an underwater platform and 12 turrets to aid in the parbuckling and hold the ship upright. The ship was winched upright using 36 cables and is being held steady on the platform with computer-controlled chains until Spring, when the ship will be floated off the platform and delivered to Sicily to be taken apart.

To view the Process Map in varying levels of detail, please click “Download PDF” above. Or, see the Cause Map about the grounding of the ship in our previous blog.