In mechanical and electrical systems, this describes a secondary reaction triggered by a primary event nearby. It most commonly refers to vibrations where a running machine causes an unpowered part to shake, or a failure where one blown component takes out its neighbor through heat or physical impact. Identifying these reactions is critical during root cause analysis to avoid replacing parts that were not the actual source of the problem.
Heard on the job
The main bearing seized up and caused a sympathetic failure in the cooling fan housing right next to it.
Insider tip
When diagnosing a blown circuit or a shattered linkage, always check if the broken part was the root cause or just a sympathetic victim of the real failure.