[Jake Raby]

Every instance has a primary failure mode. From there, the secondary, tertiary and other failures will stem.

Often times the primary failure is either misdiagnosed, or is confused with secondary failures.

A good example is a failed scavenge pump that appears to be a primary failure, BUT the reality really is a timing chain that failed and a piece of it's roller found its way into the oil. The scavenge pump picked that up, and caused the pump to seize. From there, the exhaust cam drive sprocket (which drives the scavenge pump) will slip and retard valve timing events greatly, kissing valves into the pistons.

Thats just one example. I could go on with those instances for days.