It was on this day in 2009 that Cougar flight 491 was conducting a routine shift change flight to the production facilities offshore Newfoundland when a mechanical failure (gearbox) caused the flight to turn around and head to shore.  Unfortunately, the helicopter never made it back to land and crashed into the North Atlantic; 17 of the 18 people on board, including the two pilots, died in the crash.  

The Transportation Safety Board identified 16 findings to the cause or contributing factors to the accident including galling on the titanium main gearbox filter bowl assembly studs, reduced preload on the studs and an inability to continue to fly for 30 minutes without main gearbox lubrication as described in the operating specifications of the aircraft.  Aircraft maintenance procedures where not effectively implemented and therefor damaged studes were not detected nor replaced.  Additionally, crew resource management issues were noted in the investigation, including the misdiagnosis of operational problems which exacerbated flying problems and combined with pilot errors prevented a controlled ditching. 

It is unfortunate that events such as this continue to happen in organizations and sectors, but this incident does highlight several lessons learned that we can take away and apply:

• Regardless of the frequency in which higher-risk tasks are undertaken, we cannot become complacent about the risks that they entail.  Simply because a task is done a lot doesn't mean it is lower-risk or even risk free.  Complacency is a risk that exists on tasks that are commonplace and “routine.”
• The successful execution of tasks, higher-risk or not, reinforces one's confidence in doing that task thus giving a sense of control, knowledge and expertise over doing that task, and therefore misjudging the potential severity of the risk associated with it. 
• Completion of required maintenance must be done as prescribed and changes to maintenance programs, intervals and types should only be done after a rigourous review.
• Drilling and training are key activities to prepare for emergency conditions and in some cases survival and should be reinforced.

Accidents continue to happen in the work-place and it is incumbent upon leaders to learn the lessons from previous incidents and apply them to their own operations.  Learning only from your own incidents is too narrowly focused, instead learn from others to prevent similar occurences in your own workplace.