|Picture embedded from HHMercer on 7 Oct 09|
Foreign Object Debris (FOD) Damage is one of the most costly problems in aircraft operations. According to The Boeing Company, foreign objects on runways have cost the aerospace industry an estimated US$4 billion in aircraft repairs, flight delays and airport maintenance annually. 
|Picture embedded from Safety1st on 7 Oct 09|
A FOD is a substance, debris or article alien to the engine, equipment or aircraft that if ingested into the engine or lodged in a mechanism, would potentially cause damage which may render the system unusable or unsafe for operation. 
Examples include ingestion of loose hardware or piece of broken pavement into an engine, hardware jamming flight controls, cut tyres from debris on the taxiways or runways.
Causes of FOD
FOD is usually caused by one or more of the following:
- Human. People primarily cause FOD, through their failure to constantly account for removed hardware, tools, paper, safety wires wtc while performing any task on or near aircraft or engine.
- Morale. If the morale or attentiveness of personnel working near or on aircraft is below par, they may fail to adopt good practices in preventing FOD ingestion. For example, if they are fatigued from working over-time or under personal stress, they are more likely to be careless and be a cause of FOD.
- Clothing and personal equipment. Parts of clothing, identification passes, items in the pockets if not properly secured can be sources of FOD. This is especially so for personnel working in the vicinity of aircraft engines. Only essential personal items shoudlb e carried in the secured pockets and accounted for after work has ceased on the aircraft.
- Transient personnel. Visitors to the flight line are sometimes responsible for FOD because they are not aware of the FOD prevention procedures. Contrators working on or near the flight line may be unwitting contributors to FOD because of careless handling of debris, poor clean up practices or pure ignorance.
- Debris. Inadequate house cleaning and policing operations after heavy rainfall and high winds can leave runways and taiways littered with stones, clods of earth and other debris. These can be ingested into the aircraft engines. bolts. screws, bits of scrap metal and other items of litter accumulated on aircraft movement areas area also sources of FOD.
- Environmental conditions. Locations close to unprepared area, beaches can expose the aircraft or sandstorms, rocks, stones. Icing conditions and hailstones are also causes of FOD. In addition, after a heavy downpour in an airfield, loose gravel and sand carried by the water gullies can also be ingested into the engine.
- Tools accountability. During aircraft maintenance, work centers must enforce established procedures in ensuring accountability of all tools at the start and end of each maintenance or rectification task.
- Hardware control. Effective procedures must be established for control of loose hardware such as nuts, bolts, rivet heads etc. When performing specific maintenance or rectification works, do not take over and above the amount of hardware that is required. Upon the completion of the specific task, all maintenance or rectification debris must be removed especially around eh engine intake. 
FOD related accident
Crash of Air France Flight 4590
Air France 4590, during its take off roll hit a piece of titanium debris on the runway which ruptured a tyre, setting up a chain of reactions which eventually caused it to crash.
|Picture embedded from Autopia on 7 Oct 09|
For a more comprehensive analysis of the accident, please refer to Air France 4590 downed by debris
Prevention of FOD
|Picture embedded from NATA on 7 Oct 09|
FOD prevention requires the active participation of each and every individual in the aviation industry by:
- Pursuing an active FOD prevention program
- Maintaining a constant surveillance of the airfield to detect FOD hazards on runways, taxiways using runway sweepers, conducting FOD walks as shown below
|Picture embedded from Daylife on 7 Oct 09|
- Ensuring that FOD incident reports are co-ordinated and handled expeditiously with the appropriate action agencies
- Maintaining incident statistics, inspection results to detect possible trend
- Following up corrective actions to ensure that FOD hazards are eliminated 
Education through training personnel and exposing them to good work practices whilst emphasizing unique local conditions and problems. highlighting the cause, cost and recommended corrective action taken in actual FOD incidents with actual case studies will help reinforce the importance of the program.
Publicity is also an important element in a successful FOD prevention program through safety bulletin boards, by publishing reports of FOD investigation actions taken to eliminate FOD hazards, new FOD prevention techniques and the use of posters around aviation facilities.
|Picture embedded from CAAS on 7 Oct 09||Picture embedded from CAAS on 7 Oct 09|
Detection of FOD
By leveraging on the latest technologies, FOD detection systems have been developed to enhance FOD detection on the aircraft maneouvring areas (AMA) so that these areas are kept under surveillance 24/7 and FOD can be detected and cleared without hampering the efficiency of aircraft operations.
An example is the system utilised in Changi Airport using the iFerretTM from Stratech Systems which was launched in 2006; this system encompasses the latest in electro-optical sensor technology to pinpoint the exact location of FOD on the AMA for accurate assessment and removal. 
|Picture embedded from Stratech on 7 Oct 09|
FOD is a perennial problem for aviation related operations and if left unchecked could cause a disastrous accident. Through FOD prevention programs, training and detection systems, FOD can be identified and eliminated so that potential hazardous situations will not materialise.
Want to know more?
- Stratech – The Future of FOD prevention
- This article provides details how Stratech leverages on the latest technological innovations in design of FOD prevention.
- FAA – FOD Detection Research
- This article provides details the amount and nature of research FAA is conducting to evaluate various technologies capable of detecting Foreign Object Debris (FOD).