Tag Archives: Cause Mapping

Today in History: Fire on the USS Enterprise

By ThinkReliability Staff

On January 13, 1969, 31 years ago, fires and explosions broke out on the USS Enterprise (CVN-65). The crewmembers spent three hours fighting the fire. When the smoke cleared, 27 crewmembers were killed and 314 were injured. Additionally, 15 aircraft were destroyed and the carrier was severely damaged.

We can address the impacts to the U.S. Navy’s goals in a problem outline as the first step of the Cause Mapping process. There was an impact to the safety goal because crewmembers were killed and injured. There was an impact to the property goal because of the 15 planes that were damaged, and the repairs that were required to the ship. (This is also an impact to the labor goal, because of the labor required for the repairs.) Additionally, the ship’s deployment was delayed, which is an impact to both the customer service and production/schedule goals.

After we’ve completed the outline, we build our Cause Map beginning with the goals that were impacted. The goals were impacted by a series of explosions and fires across the ship. These explosions and fires were fueled by jet fuel and bombs that were found on the planes on the flight deck of the carrier. The initiating event was the explosion of a Mk-32 Zuni rocket, which exploded when it overheated due to being put in the exhaust path of an aircraft starting unit.

After the incident, the Navy performed an investigation to review the causes of the incident, and made changes to improve safety. Repairs to the Enterprise were completed, and the ship is now the oldest active serving ship in the U.S. Navy.

A thorough root cause analysis built as a Cause Map can capture all of the causes in a simple, intuitive format that fits on one page. To view the downloadable PDF, click “Download PDF” above.

Grounding of the Empress of the North

Download PDFby Kim Smiley

On May 14 2007, the 300 foot cruise ship, Empress of the North, grounded out on rocks while rounding Rocky Island during a trip through Alaska’s Inland Passage.  There was significant damage to the hull and the two starboard propellers needed to be replaced.  Costs of repairs totaled more than $4.8 million.  Luckily no one was injured, but over two hundred passengers had to be evacuated from the ship.

This is a common route for cruise ships and the rocks were a well-known hazard clearly marked on navigation charts.  So what happened?

A root cause analysis shows that there were many causes that contributed to the accident.  One of causes is that there were no lookouts at the time of the accident.  The crew members who would have acted as lookouts were performing security rounds.  This was in violation of regulations requiring lookouts at all times and appears to have been a common practice for the crew.

When determining causes it’s important to ask, what is different?  In this case, this was the first watch as Deck Officer for the officer in charge.  He had recently graduated, was newly licensed and inexperienced.  He was not familiar with the deck procedures and the equipment. There was a lot of confusion about watch team roles and he didn’t attempt to take charge of the ship’s navigation until seconds before the grounding occurred.  The National Transportation Safety Board (NTSB) found that the actions, or inaction as the case may be, of the Deck Officer were one of the major factors contributing to the accident.

It’s tempting to stop at this point, but the analysis needs to go farther than just identifying the actions of the Deck Officer as a cause to do a thorough investigation.  Why was he standing watch if he wasn’t fully qualified?  Why wasn’t he prepared adequately prior to being given the responsibility?

The crew member originally assigned the watch was ill.  There are a limited number of possible replacements on a ship this size.  The Master of the ship believed the watch would be a good training watch because it was an easy watch with minimal course corrections needed.  It was also not the practice of the crew to have specific night orders for the overnight watches so the newly arrived junior third officer found himself standing the midnight to 4 am watch with minimal guidance.

Many investigations lead back to human error, but it’s important to ask questions beyond that point.  Changing how people are trained, improving the environment, and providing specific writing inspections can help prevent human errors in many cases.

(The photo above is an official Coast Guard photo.)