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Foreign Object Damage (FOD) Prevention is an unending challenge for all aerospace operators. There is a need to develop standardized terms, procedures and methods for the prevention and processing of foreign object damage to aircraft and aerospace vehicles. The objective of this document is to make the Bases/Units aware of the need to eliminate foreign object debris and provide information about current proven practices and technological advancements that prevent FOD.
CHAPTER – 1
The purpose of this Précis is to establish a guideline for the Bases/Units to prevent foreign object damage (FOD). Most FOD can be attributed to poor housekeeping, facilities deterioration, improper maintenance or careless assembly and inadequate operational practices. An effective FOD Prevention and Control précis identifies potential problems, corrects negative factors, provides awareness, effective personnel training, and uses “lessons learned” for continued improvement. The objective of the FOD Prevention and Control Guideline is to promote ground and flight safety and the preservation of Operational assets. This process is intended to be used as a baseline for FOD prevention. Users are encouraged to apply the contents of this guideline to suit their particular weapon system and environment. These Guidelines do not present the final word on the subject; rather it envisages continual input and improvement by the users by streamlining it to their peculiar needs relevant to user specific needs.
CHAPTER – 2
GENERAL INFORMATION ON FOD
This guideline establishes general workmanship practices and standard terms for the prevention of Foreign Object Damage (FOD) to Aircraft engines by associated ground support equipment, work practices, operating surfaces and environment. The guidelines shall facilitate in improving awareness work practices and procedures and help in effective FOD management.
The definitions given below shall help in understanding the terminologies being used frequently and to standardize the comprehension of our personnel.
Foreign Object Debris. A substance, debris or article alien to a vehicle or system which would potentially cause damage.
Foreign Object Damage (FOD). Any damage attributed to a foreign object that can be expressed in physical or economic terms which may or may not degrade the product’s required safety and /or performance characteristics.
Aircraft Object Debris. Any hardware or component falling off from an aircraft where it can potentially cause damage to any aircraft.
Aircraft Object Damage. When an aircraft encounters damage due to Aircraft Object Debris.
Internal Object Damage. When damage to an aircraft or engine is caused by a hardware or component belonging to the same aircraft.
FOD Area. An area sensitive to FOD ingestion like pitot boom intake without cover or any other area where FOD can easily migrate to invisibility and cause damage.
Potential FOD. The condition where foreign object debris may cause damage, and/or failure should the product be put into use. Examples are: –
Metal or wire clippings, solder balls and debris lying in the vicinity or electrical terminals, circuitry, connectors, components, etc
Tools, hardware, or debris left in the vicinity, or in a migratory path or a vehicle’s control system or engine inlets
Debris lying on runways, ramps and taxiways
Prop wash exhaust blasts
Ice and salt
Birds and other animals
Electro-Static Discharge (ESD)
Critical FO. Foreign objects in areas from which migration is possible, e.g., through tooling holes, bend relief cutouts, drains, intakes, etc., which are probable to cause system or component malfunction or deterioration should the product be put into use.
FOD Critical Area. An area sensitive to FOD ingestion like Pitot boom or intake without cover or any other area where FOD can easily migrate to invisibility and cause damage.
Foreign Object Elimination (FOE). A program or process used to assure FOD-free product/system.
Tote Tray. A device for storing/carrying/transporting tools or equipment in a secure manner to prevent inadvertent dropping: i.e., a tool holder, an apron with pocket rings to which tools can be secured. Tote trays with lids will have the lid secured to the tote tray body.
Clean As You Go.
Clean the immediate area when work cannot continue.
Clean the immediate area when work debris has the potential to migrate to an out of sight or inaccessible area and cause damage and/or give the appearance of poor workmanship.
Clean the immediate area after work is completed and prior to inspection.
Clean at the end of each shift. Where shift end refers to cease of work for individual technician.
If you drop something or hear something drop – pick it up!
Consumables. Supplies provided to workers that are expendable. Examples are:-
Issued apparel safety glasses
Glue, paint, sealant, rags
Sandpaper, brushes, applicators
Stock items such as rivets, washers, fasteners and other hardware.
Shadowbox. A toll box with specific, marked location for each tool so that a missing tool is readily noticeable.
Tether. A lanyard of sufficient strength (wire, rope, cable, etc.) attached to the tool/equipment and to the user or fixed secure object to facilitate quick recovery in case of tool loss. The tether should be minimum length to preclude damage from tethered tool “free swing.”
CHAPTER – 3
IMPLEMENTATION OF FOD CONTROL METHODS
Every Base / Unit / Area / Location offers different FOD environment and challenges which also change with time. Bases / Units must establish and maintain an effective FOD prevention programme relevant to their own environment that is thoroughly planned and implemented using the continuous improvement approach. Lessons learned from past instances are minimum input for such plan and new construction activities must also be an input to proactively examine potential effects on current used areas like taxiways and run-up areas.
FOD Prevention Training
System Specific considerations for FOD prevention, in relation to operating surfaces and overall environment.
Maintenance practices/ techniques that include proper care and use of assembly/maintenance equipment and parts protective devices.
Handling of material
Control of tools and personal items
Control of hardware/consumables
Measuring techniques for analysis, trending, and feedback
Control of hazardous material
For effective FOD prevention, the following practices must be established and encouraged: –
Practice good housekeeping, “Clean-As-You-Go.”
Account for all tools, hardware and equipment at specific intervals.
Use x-ray, borescope, and other state-of-the-art equipment to inspect inaccessible areas available in industry from time to time.
Provide worker awareness of / about FOD causes.
Establish designated storage areas for ladders, hoses, tool boxes and other work aids.
Feedback through benchmarking with proven practices within PAF or anywhere in aviation industry.
CHAPTER – 4
Performance Measuring Tools
The operational target in any FOD prevention programme should always be “zero” FOD. The programme should also enable visibility to problem areas and trends provide management and workers with inspection results, incident / mishap reports, and feed back of progress. Methods providing this information are: –
Visibility Charts. Statistical graphics derived from audit or incident data. Usually provided on an isochronic schedule, i.e., weekly or monthly. Unit FSO and Base FSO are to play lead role in this area and present data in Unit / Base meeting.
Trend Analysis. Where have you been? Where you are? Where are you going?
Performance Review. A review of worker conformance to standards or expectations. While number of FOD occurrences is an indicator of performance, total rupee value lost due to FOD is another count for performance review. Vide circulation in terms of cost to increase awareness to the extent of damage is essential to bring a paradigm shift in terms of realization of all concerned
Feedback and Control
Workers need specific information about what is wrong before they can be expected to improve processes. Let them know when they’re doing well or when they’re not. Feedback is vital to process improvement and QAO / FSO has to continually play vital role on this account. A proactive approach with a realistic and practical approach is required.
CHAPTER – 5
The primary objectives of an FOD prevention training program is to increase general awareness to the causes and effects of FOD, promote active involvement through specific techniques, and stress good work habits through work disciplines.
An FOD prevention training Program for personnel associated with design, assembly, test, operations, repair, modification, refurbishment, and maintenance is required as part of initial job orientation and on a continuing basis and as a continuous process thereafter.
Topics to be discussed during training are listed below. The list is not exhaustive and may be improved with experience.
Proper storage, shipping and handling of material, components, and equipment.
Techniques to control debris
Cleaning and inspection of components and assemblies
Accountability/control of tools and hardware
Control of personal items, equipment and consumables
Care and protection of end items
Quality workmanship (“Clean-As-You-Go,” Inspection)
Flight line, taxiway and ramp control methods
How to report FOD incidents or potential incidents
CHAPTER – 6
FOD CONTROL ELEMENTS
Material Handling and Parts Protection
A well established plan for material handling and parts protection can eliminate many potential FOD hazards. First, identify the specifics such as sensitive parts, assemblies, surfaces, areas, etc. Then, sequence events for packaging, handling, shipping and storage, and finally, evaluate cleanliness and care requirements.
Some guidelines for FOD management are given below: –
All personnel should be trained to assure compliance with packaging, handling, transportation and storage requirements.
Materials and accessories used in the packaging, handling, transportation and storage which have intimate contact with the part or assembly should be clean and free of contamination
Parts and assemblies should be packaged in a manner that will preclude any chance of one item making contact with another during normal handling.
Protective and packaging materials should be chosen based on their ability to adequately resist penetration by tearing, parting or piercing from forces either external or internal during normal handling operations.
Specific instructions for packaging / unpackaging / handling must be made / available to the worker.
Protective devices (edge protectors, caps, plugs, covers, filters, rub strips blanks) should be cleaned and secured to prevent accidental damage. Once installed, unauthorized removal of the protective devices is prohibited and should be controlled through assembly or maintenance paperwork / documentation.
Consideration should be given to the visibility/detection of material used for Protection so that the material in itself doesn’t become FOD. Consideration should include:
Color of packaging or protective devices so they don’t appear to be a part of what they are protecting
Streamers for removal for critical items
(h) A well defined effort must be put in to identify the possible sources of FOD from aircraft and support equipment. FOD Focal Point is responsible for identification of FOD collected from the runway and taxi-ways. This can be effectively done by showing the FOD to different work centers for identification. Based on this effort, work centers are responsible to mark vulnerable areas for FOD and include in routine inspections to preclude any chances of FOD hazard.
Visually inspect all packaging, handling, transportation and storage containers for the following:
Nicks, dents, holes, abrasions, scratches, bumps, etc., which may be detrimental to the function and integrity of the part or assembly.
Grease, preservatives, corrosion products, weld slag and other materials foreign to the item.
To avoid FOD, maintenance, manufacturing and operational areas must remain clean. Employees should be informed that housekeeping is a part of their job and they will be graded on their performance, Incorporate “Clean-As-You-Go” concept as a required work ethic to prevent debris from migrating into flight hardware.
Ensure that all production, maintenance and test areas meet “good housekeeping” standards that enhance foreign object elimination. This includes sweeping and vacuuming production areas as well as a regular sweeping of ramp/test areas.
Assure that taxiways, runways, and flight lines are free of foreign objects that may cause damage.
Ensure that grounds and surfaces on which Aircraft and ground support equipment are operated and maintained are free of objects that could cause damage by ingestion of foreign object or jet blast effects.
Establish and maintain safe taxi distances between aircraft to minimize the danger of debris being moved by the jet blast exhaust or rotor wash.
Ensure prior to the occupation of newly constructed aircraft facilities that all construction debris (including overhead welding slag) is removed as a foreign object elimination measure.
In the refurbishment or maintenance of existing airfield facilities or construction of new facilities, assure that all construction debris is removed at the end of each task and each shift. This requirement should be entered as contractual agreements.
The primary objective of a positive tool accountability program is to eliminate accidents/incidents and loss of life or equipment due to tool FOD. There are numerous methods to facilitate accountability: use of shadow boards, shadowboxing, bar coding, special canvas layouts with tool pockets, tool counters, chit system tool tags, or consolidated tool kits.
Tools/equipment should be tethered or suitably restrained to the user in areas around structural work stands or any other locations where a dropped article could result in damage to engines, injury to personnel, or where difficulty in retrieval would result if the tool were dropped. All loose tools should be contained in a tote tray, soft tool bag or other suitable spill-proof container and not placed in a manner that would cause damage to flight hardware or injury to personnel.
The primary objective of hardware accountability is to assure control. There are many methods that can be established for control of hardware (nuts, bolts, screws, cotter pins, rivets, etc.): –
Kit hardware by task
FOD containers should be placed in key locations within the work area and entry and exit points.
Development of “Clean-As-You-Go” concept.
Removal/installation paperwork to track loose parts.
Furnish and specify tote trays.
Covered spring-loaded containers.
Shake down inspections of aircraft and support equipment structure to arrest loose hardware.
Any time an item is lost during assembly, manufacturing, or maintenance, cease activity in the affected area and initiate a search for the item. Continue this search until the item is found or adequate assurances are made that the item is not in the aerospace vehicle or assembly. Searching for such items may require de-paneling or nondestructive inspections, including borescope and / or x-ray. If an item cannot be located after a search has been completed, annotate applicable forms with a description of the item and search procedure followed.
9. The FOD in shape of loose screws and rivets is on the rise as the age of the aircraft increases, contents of a very comprehensive study by an operational base is attached as Annex II to this document.
Physical Entry into FOD Critical Areas
10. When physical entry is required into flight hardware, such as crew compartments/cockpit, engine intake, exhaust, fuel tank areas, etc., personnel should remove all loose objects, badges, jewellery, etc., from clothing. Pocketless coveralls should be worn to preclude foreign objects dropping from pockets onto a FOD critical area else pockets should be emptied.
QA Office (Focal Point)
11 Keeping in view the resources and expertise available QA Squadron is designated as the focal point of the FOD Prevention Programme. Where office of QA does not exist, Area Commanders are to assign a Focal Point. The designated Foreign Object Damage prevention Focal Point should develop and implement plans and programs to prevent hardware damage during associated design, manufacturing, assembly, test, acceptance, packaging, handling, storage, transporting, maintenance, flight line, and launch operations. The focal point(s) duties should include: –
Review and assess the FOD prevention program and make necessary revisions.
Conduct scheduled audits of work areas to assess effectiveness of the FOD prevention program.
Assure implementation of corrective actions for FOD prevention throughout the organization.
Assure that FOD incidents are thoroughly investigated and that incident reports are completed as applicable.
Assure that causes of FOD incidents are thoroughly analyzed to define essential corrective measures.
Notify affected organizations and personnel of unique FOD prevention requirements.
Develop techniques and assign responsibilities for communication of special FOD prevention instructions.
Review results of the FOD incident investigations and evaluate adequacy of corrective actions.
Evaluate the amount and kind of foreign objects found and how they were found to trace source of FOD and workout its elimination.
Product Design Considerations
12 Begin the reduction of damage potential and elimination of FOD hazards by using the design of the engine: –
Identify and eliminate foreign object entrapment areas
Identification and sealing of areas through which foreign objects can migrate.
Use screens over exposed openings when appropriate: e.g., intakes, exhausts, etc.
Installation of special access panels, ports, etc., for inspection and clean-out of foreign objects that could potentially cause damage
Use of blind fasteners in critical areas, such as fuel cells, that are not prone to leaving debris during installation.
Use fasteners with self-retaining features to secure high usage access panels.
Locating service points, ground points, and built-in test equipment in areas which are least FOD sensitive.
Use of compatible metals and seals to prevent accelerated deterioration and subsequent failure of seal materials
Use conformal coatings as a positive sealing against entry of minute foreign objects including dust and water vapor.
Check aircraft inlets to minimize traps where water can collect and freeze.
Provision of screening or other means of foreign object blockage for water drainage holes forward of the engine inlet path.
Procedures that include provisions for FOD incident feedback and appropriate corrective action.
13 Plan and sequence maintenance/assembly tasks to preclude foreign object damage and entrapment of debris or contamination. Documents should contain necessary processes and procedures for controlling and removal of contamination and debris during fabrication and assembly operations. As applicable, the following should be included in work instructions: –
Upon completion of final machining operation, clean or flush the machined component to assure that it is free of debris, and immediately cap or seal exposed openings to deny foreign object entry.
Adequately protect hardware and equipment from splatter accumulation during brazing, soldering, welding and like operations.
Inspect components and equipment for damage prior to installation and repair as necessary. Always ensure part integrity before installation.
Test Facility Environment
14 When products are in a test facility environment, FOD / IOD prevention procedures should include, but are not limited to, the following: –
Assurance that adequate preventive maintenance is performed on the test facility.
Inspect the test cell and facility equipment for deterioration or damage and assure that deficiencies which present a FOD / IOD hazard are corrected prior to test cell operations.
Inspect the area before introduction of the engine to the test environment to ensure that it is clean. Also ensure that tools are secured, fixtures, dollies and special test equipment are properly prepared and secured, and that required protective devices (engine inlet screens, covers for engine components and instruments, etc.) are on hand, clean and undamaged.
Visually inspect the test engine before it is placed in the test cell, removal of loose objects and installation of the necessary protective devices.
Ensure test equipment, tools and accessories are maintained and used in a manner to protect test articles from damage or contamination through tool abuse or in-use failure (chipping, cracking, peeling, fraying, etc.)
Prior to start, visually inspect engine intake/exhaust areas for potential FOD and rotate the engine through sufficient revolutions to ascertain if there is unusual noise or binding condition. Instrumentation lines, hoses and wires should be taped or clamped to eliminate vibratory failure. Use of lockwire or cotter pins for this purpose should be prohibited.
Upon completion of each test article run and prior to removal from the test cell, inspect test article for presence of FOD and install protective covers.
15 Field operations may primarily involve scheduled modifications, inspections, care and maintenance of ramps, structures, runways, and taxiways. A comprehensive, scheduled maintenance system using sweepers and frequent inspections will provide some confidence, but additionally, special considerations may include: –
Tarmac repair methods/materials and frequency of inspections.
Vehicular traffic patterns and controls; i.e., all vehicles should be driven on paved surfaces when possible. If a vehicle must be driven on an unpaved surface, the operator should check the vehicle tires for foreign objects immediately after returning to the pavement. Vehicular traffic plan to be made and implemented by SATCO.
Support equipment cleanliness – items used in and around aircraft must be FOD free and should be inspected prior to movement.
Sweeper effectiveness – just because a sweeper is used, does not mean it is effective. Routinely check sweeper routes and speed to assure cleanliness. Also, sweeper brushes made with metal bristles or spines should not be used. Cyclic training of the sweeper operator and the settings of the magnet bar needs to be consistently standardized.
Flight line workers and rep(s), (if any) should be briefed and continually reminded of expectations related to foreign object damage and adhered to.
A flight line traffic plan depicting routes to be used by all approved support vehicles requiring access to buildings on or around the flight line should be developed and posted.
Routine inspection of areas used by contractors, tenants, and concessionaires for staging equipment, load/off-load, operations, etc.
Include FOD prevention considerations in the design, contracting award, and construction management for all airfield projects.
Daily and periodic inspection of aircraft structure and intake must be emphasized regularly to arrest potential FOD hazard due to loose hardware.
An FOD walk / drill before start of day’s work during the day and at required frequency can be an effective way of reducing damage due to FOD.
16 All Bases and Units are to hold monthly FOD / AOD / IOD performance review meeting covering at least all FOD / AOD / IOD cases that occurred in last six months. The meetings are to be organized by focal point (FSO). The meeting should thoroughly examine undetermined cases, current FOD / AOD / IOD findings and recommendations and minutes of meeting of stake holders as per para 8 of Chapter 7.
17 In case of no FOD during the last six months, FOD performance review meeting may not be held and it may become an agenda point of monthly Flight Safety Meeting.
CHAPTER – 7
REPORTING / INVESTIGATION
All incidents of actual or potential FOD / AOD / IOD should be reported and investigated. When an FOD / AOD / IOD incident occurs an investigation must be initiated to determine the cause. Cause and corrective action should be attained in a timely manner to preclude similar occurrences from happening in the future – “lessons learned.” Cause may be determined by visual observation, forensic analysis, or by location of the object. The investigation must identify whether the incident occurred due to FOD / AOD / IOD. In case investigation is unable to identify the debris then it is to be finalized as FOD.
Procedures outlined in AFO 62-1 should govern procedures of reporting and investigation. All events of FOD shall be classified as incident or higher. Cost of damage should be established by concerned depot which shall determine the final classification. Investigation of FOD / AOD / IOD cases should invariably be through Formal Investigation or BOI as appropriate and not through technical investigation.
An FOD / AOD / IOD incident report format should include the following: –
Part name (nomenclature)
Type and/or model
Part serial number
Narrative description of FOD / AOD / IOD – when analyzed – who analyzed – how analyzed
If FOD / AOD / IOD incident is discovered after flight operations: –
Ground / flight maneuvers performed
Aircrew contact phone number
Time/sequence of events
These reports should be directed to the FOD / AOD / IOD Focal Point who should perform tracking and trending analysis. The focal point should also assure all affected personnel are aware of all potential (near mishap) /actual FOD / AOD / IOD reports to facilitate feedback (“lessons learned”).
Where a foreign object exists but cannot be eliminated, found or effectively sealed; identify, document and record all significant search activity in the appropriate aircraft paperwork.
A “near mishap” is one where FOD / AOD / IOD incidents would have occurred had the event remained undetected. Documenting near mishap incidents and sharing them with workers is another important part of feedback, awareness and “lessons learned.”
When a narrow identification of when and how FOD / AOD / IOD occurred is not possible a round table conference of stake holders must be held. Efforts should be made to identify possible causes and time frame of FOD / AOD / IOD through a process of elimination. The round table conference must include aircrew who recently operated the aircraft, ground crew who gave engine ground run, EO, line staff and DATCO. Minutes of such meetings should be submitted to AHQ with investigation report.
Instances can happen where an engine is received at a shop or depot or factory for scheduled / unscheduled maintenance and is reported by damage due to foreign object. It is important to ascertain if FOD / AOD / IOD is caused at depot or before shipment to depot. Such investigation must be credible and Safety Board is to render credibility to such efforts. Once it is determined that FOD / AOD / IOD occurred before shipment, the Factory / Depot / Base is to refer the matter to concerned Base for investigation. The investigation should not hinder repair / overhaul and the repairing agency is to provide description of damage to the Base to facilitate investigation.
CHAPTER – 8
FOD PREVENTION PROGRAMME
1. In order to have a standardized document covering all aspects of FOD counter and preventive measures all operational activity bases (MOBs and FOBs both) should formulate a programme under the name of ‘FOD Prevention and control Programme’. The spirit of this document is to be in line with overall PAF FOD counter measures and is to encompass essential areas that make an effective part of this activity in general. The specific details are left to the users but are to essentially have certain specifics applicable to all.
FOD Prevention Programme
2. FOD Prevention Programme is essentially to cover the under mentioned:
(a) Scope and Introduction
(b) Sketch of Operating Surfaces
(c) Sketch of Operating Surfaces Showing Area Allocation and Responsibility
(d) Identification of Users
(e) Responsibilities of Users
(f) Availability of Resources
(g) Allocation of Resources
(h) Collection Process
(j) FOD Drills
(k) FOD Identification Process
(l) Specific Counter Measures
(m) Segregation of Collected FOD
(n) FOD Reporting System
FOD Prevention Programme is to be formulated at the respective bases keeping in mind their specific working environments, after finalization at the base level it is to be submitted to AHQ (Directorate of Flight Safety) for approval. The Programme would be reviewed annually with an analysis of the FOD cases being reported to AHQ (Directorate of Flight Safety). A sample FOD prevention programme devised by an operational base is attached as ANNEX I to this document.
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