FOD is an acronym for Foreign Object Debris (or sometimes Foreign Object Damage). FOD is extremely dangerous to any moving machine as it can jam moving parts, cause electrical shorts, or cause further FOD-related damage. Visual inspection technicians will often plan inspections with the intent of preventing this maintenance defect by catching the early warning signs that it may occur. FOD is also the culprit in many non-routine and shutdown maintenance procedures, as it can cause a complete malfunction of the machine affected. At its best, it can be a minor nuisance and easily removed with minimal downtime. At its worst, it can call for a complete Teardown or MRO (maintenance, repair, and overhaul) of the plagued machine.