Foreign object damage

Foreign object damage to the compressor blades of a Honeywell LTS101 turboshaft engine on a Bell 222, caused by a small bolt that passed through the protective inlet screen
FOD deflection system on a PT6T installed on a Bell 412. Air enters from upper right, and pure air follows the curved ramp down to the compressor inlet (also covered by a screen). Any debris being sucked in will have enough momentum that it will not make such a sharp bend, and will hit the screen on the upper left, and will be carried out to the left, getting blown overboard.
Potential foreign object debris (in this case, a Scops owl) found in the wheel well of an F/A-18 Hornet on a US aircraft carrier

In aviation and aerospace, the term foreign object damage (FOD) refers to any damage to an aircraft attributed to foreign object debris (also referred to as "FOD"), which is any particle or substance, alien to an aircraft or system which could potentially cause damage to it.[1]

External FOD hazards include bird strikes, hail, ice, sandstorms, ash-clouds or objects left on a runway or flight deck. Internal FOD hazards include items left in the cockpit that interfere with flight safety by getting tangled in control cables, jam moving parts or short-out electrical connections.

  1. ^ Cite error: The named reference ForeignObjectDebrisAndDamagePrevention was invoked but never defined (see the help page).