Tag Archives: Delay

Root Cause Analysis - Incident Investigation

$3 Bolt Causes $2.2 million in Damages to US Submarine

By ThinkReliability Staff

A $3 bolt was left in the main reduction gear of the USS Georgia after a routine inspection.  The extensive damage caused by the bolt resulted in 3 months in the shipyard for the submarine, causing it to miss deployment.  The propulsion shaft was left to operate for two days after sounds indicated that there was something wrong.  This may have increased the damage to the main reduction gear – damage which cost $2.2 million.

How did the bolt end up in the main reduction gear? Why was the propulsion shaft operated for 2 days after damage was suspected?

We can look at the causes that led to this incident in a Cause Map, a visual root cause analysis that clearly outlines cause-and-effect relationships that result in impacts to an organization’s goal.  The first step to building a Cause Map is to determine how the issue impacts the organization’s overall goals.  Here we can consider the US Navy as the organization.  The customer service goal (with the rest of the country as the “customers”) was impacted because the submarine was unavailable for deployment.  The production/schedule goal was impacted because the submarine was in the shipyard for  three months.  The damage to the main reduction gear is an impact to the property goal, and the repairs are an impact to the labor/time goal.  The total cost resulting from this issue was estimated to be $2.2 million.  Once the impacts to the goals have been determined, we can ask why questions to put together the cause-and-effect relationships that led to these impacts.

The bolt was left behind after a routine, annual inspection.  Because of the great potential for damage when foreign objects remain within equipment, detailed procedures are used for these inspections and include a log of all equipment brought into the area and a protective tent to keep objects from falling in.  Details of what went wrong that resulted in the bolt falling into the main reduction gear were not released, but the inspection was reported to have “inadequate prep and oversight” which likely contributed to the issue.

After the propulsion shaft was turned back on, noise indicated that there was a problem.  However, the shaft was operated for two days in a failed attempt at troubleshooting.  It’s likely that this increased the damage to the main reduction gear.  It is unknown what procedures were – or should have been – in place for troubleshooting, but the actions taken as a result of this incident suggest that proper procedures were not followed once the damage was suspected.

In this case, members of the crew who were found to not have performed their job – possibly by not following proper procedure – were punished in varying ways.  It is likely that the investigation went into great detail about whether procedures were adequate, what steps were not followed, and why, and the results also used to improve procedures for the next inspection.

To view the Outline and Cause Map, please click “Download PDF” above.

Root Cause Analysis - Incident Investigation

First Airline Fine for Tarmac Delay

by Kim Smiley

The Department of Transportation (DOT) recently issued the first fine for violating new rules that limit how long passengers can be kept onboard a plane waiting on the tarmac. The new regulations, commonly called the tarmac delay rule, state that passengers may not be kept onboard a plane waiting on the runway for more than 3 hours without being given the opportunity to deplane.  The rules also require that airlines provide adequate food and drinking water for passengers within 2 hours of a plane being delayed on the tarmac and to maintain operable lavatories.  The tarmac delay rule, which went in effect April 2010, was created following several incidents where passengers were kept onboard airplanes for long periods of time.

The incident that resulted in a fine is not the first violation of the 3 hour rule, but this is the first time the DOT has taken the step of issuing a fine.  The potential fees for violating the rules are substantial.  Airlines can be fined $27,500 per passenger when the tarmac delay is beyond 3 hours.  This quickly adds up, especially if multiple flights are involved.  In this example, 15 American Eagle flights were delayed beyond the 3 hour limit on May 29, 2011 at O’Hare International Airport in Chicago.   608 passengers were affected and American Airlines was fined a whopping $900,000.

What happened?  How were so many flights on the tarmac so long?

This example can be analyzed by building a Cause Map, a method for performing a visual root cause analysis.  A Cause Map is built by determining the cause-and-effect relationships between all the causes that contributed to an incident.  Click on “Download PDF” above to view a high level Cause Map of this incident.

As with many airline delays, inclement weather played a major role in this incident.  Flights had been delayed taking off from O’Hare and planes that were scheduled to have departed were still sitting at the gates.  Planes that landed had nowhere to go so they sat on the tarmac waiting for an open gate.

Passengers were not given an opportunity to deplane within 3 hours.  The airline has procedures to get passengers off the planes even if the planes themselves were stuck waiting on the tarmac, but the procedures were not implemented within the 3 hour time limit.  If there was no delay limit, an airline couldn’t violate it so the new creation of the tarmac delay role is also a cause to consider in this incident.

It will be interesting to see how this large, first of its kind fine affects the airline industry as a whole.   Statistics show that the new rules have successfully reduced long tarmac delays.  The first year that the rule was in effect, airlines reported only 20 tarmac delays of more than 3 hours, but in the 12 months prior to rule there were 693 delays of more than 3 hours.  But this improvement may come at a high cost.  Especially now that the DOT has shown that they are willing to issue fines, industry analysts are warning that a possible unintended consequence of the new tarmac will be more canceled flights.  The fines are so hefty that airlines may cancel entire flights rather than risk violating the tarmac delay rules, which would obviously have an impact on travelers.  Only time will tell how the new rules will affect airline travel.

Root Cause Analysis - Incident Investigation

Space Shuttle Launch Delayed

By ThinkReliability Staff

Launching a space shuttle is a complicated process (as we discussed in last week’s blog).  Not only is the launching process complex, finding an acceptable date for launch is also complex.  This was demonstrated this week as the shuttle launch was delayed four times, for four separate issues and now will not be able to happen until the end of the month, at the earliest.

There are discrete windows during which a launch  to the International Space Station (which is the destination of this mission) can occur.  At some times, the solar angles at the International Space Station would result in the shuttle overheating while it was docked at the Space Station.  The launch windows are open only when the angles are such that the overheating will not occur.

The previous launch window was open until November 5th.  The launch was delayed November 1st for helium and nitrogen leaks, November 2nd for a circuit glitch, November 4th for weather, and November 5th for a gaseous hydrogen leak.  After the November 5th delay, crews discovered a  crack in the insulating foam, necessitating repairs before the launch.  These delays pushed the shuttle launch out of the available November launch window.  The next launch window is from December 1st through 5th, which gives the shuttle experts slightly less than a month to prepare for launch, or the mission may be delayed until next year.

Although not a lot of information has been released about the specific issues that have delayed the launches, we can put what we do know into a Cause Map.  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.  Once more information is released about the specifics of the issues that delayed the launch, more detail can easily be added to the Cause Map to capture all the causes for the delay.  Additionally, the timeline can be updated to reflect the date of the eventual launch.

To view the problem outline, Cause Map, and launch timeline, please click on “Download PDF” above.