Fatal Bridge Collapse Near Cincinnati

By Kim Smiley

On the evening of January 19, 2015, an overpass on Interstate 75 near Cincinnati collapsed, killing one and injuring another.  The overpass was undergoing construction when it unexpectedly collapsed onto the road below it, which was still open to traffic.

This incident can be analyzed by building a Cause Map, a visual root cause analysis, to intuitively lay out the many causes that contributed to an accident by showing the cause-and-effect relationships.  Understanding all the causes that played a role, as opposed to focusing on a single root cause, expands the potential solutions that can be considered and can lead to better problem prevention.  A Cause Map is built by asking “why” questions and documenting the answers.

In this example, a construction worker was operating an excavator on the overpass when it collapsed.  When the bridge collapsed the worker was crushed by the steel beams he was moving.   The additional weight of evacuator and steel beams on the overpass likely contributed to the collapse.   The overpass was being demolished as part of a project to remake this section of the Interstate and a portion of the overpass had already been removed.  The work that had been done appears to have made the structure of the bridge unstable, but the construction company was not aware of the potential danger so the worker was operating on top of the overpass and the road beneath it was still open to traffic.

A truck driver traveling under the overpass at the time of collapse suffered only minor injuries, but came within inches of being crushed by the bridge. It really was simple luck that no other vehicles were involved.  Had the collapse happened earlier in the day when there was more traffic, the number of fatalities may very well have been higher.  As investigators review this accident, one of the things they will need to review is the fact that the road below the bridge was open to traffic at the time of the collapse.  An additional relevant piece of information is that the construction company had financial incentives to keep the road open as much as possible because they would be fined for any amount of time that traffic was disrupted.

In addition to the safety impacts of this accident, the overpass collapse dramatically impacted traffic on a busy road with an estimated 200,000 vehicles traveling on it daily.  It took nearly a day to get all lanes of the interstate cleaned up and reopened to traffic.  No one wants to close roads unnecessarily and the goal of minimizing traffic is an excellent one, but it has to be balanced with safety.  The collapse of the overpass wasn’t an unforeseeable random accident and the demolition needs to be done in a safe manner.

Prison Bus Collides With Freight Train

By Kim Smiley

On the morning of January 14, 2015, a prison bus went off an overpass and collided with a moving freight train.  Ten were killed and five more injured.  Investigators believe the accident was weather-related.

This tragic accident can be analyzed by building a Cause Map, a visual root cause analysis.  A Cause Map visually lays out the cause-and-effect relationships to show all the causes (not just a single root cause) that contributed to an accident.  The first step in the Cause Mapping method is to determine how the incident impacted the overall organizational goals.  Typically, more than one goal needs to be considered.  Clearly the safety goal was impacted because of the deaths and injuries.  The property goal is impacted because of the damage to both the bus and train (two train cars carrying UPS packages were damaged).  The schedule goal is impacted because of the delays in the train schedule and the impact on vehicle traffic.

The Cause Map itself is built by starting at one of the impacted goals and asking “why” questions. So why were there fatalities and injuries?  This occurred because there were 15 people on a bus and the bus collided with a train.  The bus was traveling between two prison facilities and drove over an overpass.  While on the overpass, the bus hit a patch of ice and slid off the road, falling onto a moving freight train that was passing under the roadway.  No one onboard the train was injured and the train did not derail, but it was significantly damaged.  The bus was severely damaged.

The prisoners onboard the bus were not wearing seat belts, as is typical on many buses.  They were also handcuffed together, although it’s difficult to say how much this contributed to the injuries and fatalities.

Useful solutions to prevent these types of accidents can be tricky.  The prison system may want to review how they evaluate road conditions prior to transporting prisoners.  This accident occurred early in the morning and waiting until later in the day when temperatures had increased may have reduced the risk of a bus accident.  Transportation officials may also want to look at how roads, especially overpasses, are treated in freezing weather to see if additional efforts are warranted.

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

You can also read our previous blogs to learn more about other train collisions:

Freight Trains Collide Head-on in Arkansas

Freight Train Carrying Crude Oil Explodes After Colliding with Another

“Ghost Train” Causes Head-on Collision in Chicago

Deadly Train Collision in Poland

Passengers trapped in smoke-filled metro train

By Kim Smiley

A standard commute quickly turned into a terrifying ordeal for passengers on a metro train in Washington, DC the afternoon of January 12, 2015.  Shortly after leaving a station, the train abruptly stopped and then quickly filled with thick smoke. One passenger died as a result of the incident and 84 more were treated for injuries, predominantly smoke inhalation.

This incident can be analyzed by building a Cause Map, a visual root cause analysis.  A Cause Map visually lays out the cause-and-effect relationships to show all the causes that contributed to an issue.  The first step in the Cause Mapping process is to define the problem by filling in an Outline with the basic background information as well as documenting how the issue impacts the overall goals.  For this example, the safety goal is clearly impacted by the passenger death and injuries.  A number of other goals should also be considered such as the schedule goal which was impacted by significant metro delays.  (To view an Outline and initial Cause Map for this issue, click on “Download PDF” above.)

So why were passengers injured and killed?  Passengers were trapped on the train and it filled with smoke.  It is unclear why the train wasn’t able to back up to the nearby station once the smoke formed and investigators are working to learn more.  (Open issues can be documented on the Cause Map with a question mark to indicate that more evidence is needed.)  There are also questions about the time emergency workers took to reach the train to aid in evacuation of passengers so this is another area that will require more information to fully understand. By some account, it took 40 minutes for firefighters to reach the trapped passengers.

Initial reports are that smoke was caused by an electrical arcing event, likely from the cables supporting the high voltage third rail used to power the trains. The specifics of what caused the arc are being investigated by the National Transportation Safety Board and will be released when the investigation is concluded.  What is known is that there was significant smoke caused by the arc, but no fire.  There have also been reports of water near the rails that may have been a factor in the arcing.

Eyewitness accounts of this incident are horrifying.  People had little information and didn’t know whether there was fire nearby at first.  They were told to remain on the train and await rescue, but the rescue took some time, which surely felt longer to the scared passengers.  It won’t be clear what solutions need to be implemented to prevent similar problems in the future until the investigation is complete, but I think we can agree that metro officials need to work to ensure passenger safety going forward.

Bad Weather Believed to Have Brought Down AirAsia Flight QZ8501

By Angela Griffith

AirAsia flight QZ8501, and the 162 people on-board, was lost on December 28, 2014 while flying through high-altitude thunderstorms. Because of a delay in finding the plane and continuing bad weather in the area, the black box, which contains data that will give investigators more detail on why the plane went down, has not yet been recovered. Even without the black box’s data, experts believe that the terrible weather in the area was a likely cause of the crash.

“From our data it looks like the last location of the plane had very bad weather and it was the biggest factor in behind the crash. These icy conditions can stall the engines of the plane and freeze and damage the plane’s machinery,” says Edvin Aldrian, the head of Research at an Indonesian weather agency. Beyond the icing of engines, there are other theories on how weather-related issue may have brought down the plane.

Early speculation was that the plane was struck by lighting; while it may have been struck by lightning, experts say it’s unlikely it would have brought the plane down, because modern planes are fairly well-equipped to deal with direct lightning strikes. High levels of turbulence can also result in stalling due to a loss of airflow over the wings. There are also some who believe the plane (an Airbus A320) may have been pushed into a vertical climb past the limit for safe operation (to escape the weather) which resulted in a stall.

While the actual mechanism of how the weather (or an unrelated issue) brought the plane down is still to be determined, aviation safety organizations are already implementing some interventions to increase the safety of air travel in the area based on some specific areas of concern. (These areas of concern can be viewed visually in a Cause Map, or visual root cause analysis, by clicking on “Download PDF” above.)

AirAsia pilots relied on “self-briefings” regarding the weather. Pilots in other locations have expressed concern about the adequacy of weather information pilots obtain using this method. Direct pilot briefings with dispatchers based on detailed weather reporting are recommended to ensure that pilots have the information they need to safely traverse areas of poor weather (or stay out of them altogether).

Heavy air traffic in the area delayed approval to climb out of storm. At 6:12 local time the flight crew requested to climb to higher altitude to attempt to escape the storm. Air traffic control did not attempt to respond to the plane until 6:17, at which point it could no longer be contacted. Air traffic in the area was heavy, possibly because:

The plane did not have permission to fly the route it was on. AirAsia was licensed to fly the route it was taking at the time of the crash four days a week, but not the day of the crash. The takeoff airport used incorrect information in allowing the plane to take off in the first place (and the airline certainly used incorrect information in trying to fly the route as well). The selection of the route has been determined not to be a factor in the crash, but it certainly may have resulted in the overcrowding that led to the delayed response from air traffic control. It also resulted in the airline’s flights on that route being suspended.

It took almost three days to find the plane. The delay is renewing calls for universal tracking of aircraft or real-time streaming of flight data that were initially raised after the loss of Malaysia Airline flight MH370, which is still missing ten months after losing radar contact. (See our previous blog on the difficulties finding it.) Not only would this reduce the suffering of families while waiting to hear their loved ones’ fates, it would reduce resources required to find lost aircraft and, in cases where survival is possible, increase the chance of survival of those on the plane.