Accident (pilot error related):
There's allways someone pouring gasoline on the ground. Sometimes there's lots pouring gasoline on the ground. These are contributing factors, casual factors and all that jazz.
Many times pilots have the zippo in their hands. When pilots light the zippo and throw it over those gallons of gas, we have pilot error primary cause. When pilots decide to throw the zippo in the pocket, we probbably have a non-accident. If pilots manage to keep away large quantities of gasoline, we have a non-event.
For one accident, we have hundreds of non-accidents, and thousands of non-events. Non-accidents may be reported, but often they go unreported (unfortunately), and many times even unnoticed.
Primary cause is the spark, the one that if didn't occur the accident wouldn't happen. That's probbably why pilot error is so commonly the primary cause, because pilots are there. Because seating in front of this computer doesn't allow me to act on a primary cause.
If our TAM coleagues acctualy failed to retard #2 throttle, that was in fact primary cause.