1. Foreign Object (FO): a substance or particle alien to the aircraft or assembly that has been allowed to invade the product.  FO is further defined as:
    1. Critical FO: foreign objects in the immediate area of or in areas from which migration is possible, e.g., through tooling holes, bend relief cutouts, drain holes, etc., and which could cause a system or component malfunction or deterioration.
    2. Noncritical FO: any FO not classified as critical.
  2. Foreign Object Damage (FOD): any damage attributed to a
    foreign object that can be expressed in physical or economic (monetary) terms which may or may not degrade the product's required safety and/or performance characteristics.
  3. FOD Prevention Program: a formal, documented, disciplined program designed to prevent FOD caused by events or conditions under control of the contractor.
  4. Potential FOD: the as-found condition where a FO is in a position to cause damage should the product be put into use.  Examples are:
    1. Tools, manufacturing and inspection hardware, and other objects left in the vicinity of or in a migratory path of engine inlets.
    2. Metal or wire clippings, solder balls, and debris lying in the vicinity of electrical terminals, circuitry, connectors, components, etc.
    3. Tools, hardware or debris left in the vicinity or in a
      migratory path of a vehicle's control system.
    4. Debris lying on runways, ramps and taxiways.