All production has been temporarily stopped as officials investigate the incident.
The FOD was found during a normal inspection and Boeing reported it to their defense contractor, according to Boeing spokesman John Williamson.
Boeing officials couldn't go any further into exactly what to FOD was or how it got onto the assembly line.
Employees are being told to still report for work as usual as an investigation into the incident is completed.
The government won't by buying any of the copters -- or anything else for that matter -- from Boeing's facility until the investigation is complete, according to Boeing.