22 INTERNATIONAL AIRPORT REVIEW l ISSUE 2 l 2008

With the data collected from theseevaluations, the FAA will be able todevelop performance standards for FODDetection Systems. It is expected that theimplementation of these types oftechnologies will greatly enhanceoperational safety at many large airportsin the United States.

The term FOD is typically used todescribe any small item, particle, or debristhat does not belong on an airportpavement surface, and has the capability tocause harm or damage to an aircraft thatpasses by (See Figure 1). In many cases,FOD is associated with military operations,where it is not uncommon to hear of ‘FOD

Walks.’ Here, ground personnel search anarea by walking shoulder-to-shoulderacross the pavement, stopping to pick upthe smallest of pebbles or debris that mayhave found its way out onto the aircraftoperations area. The goal is to remove allparticles that could potentially hit anaircraft or even be ingested by an aircraft’sengine; an event that no pilot or airportoperator wants to happen.

For civilian airports, the same concernfor FOD exists, but the resources toconduct a military-style FOD Walk just donot exist. Instead, airport operators arelimited to regularly scheduled ‘airportinspections’ where they patrol the airport

TECHNOLOGY l FOD DETECTION

Foreign ObjectDebris (FOD)detection researchThe Federal Aviation Administration (FAA) is conducting research to evaluatevarious technologies capable of detecting Foreign Object Debris (FOD), thatmay have fallen onto a runway or taxiway. The research being conducted underthis program is very aggressive, calling for the installation of differentdetection technologies at major United States airports, along with a verythorough evaluation process that assesses performance under a full range ofweather and operational conditions.

Jim Patterson JrAirport Safety Specialist, FAA

Jim Patterson Jr. is an Airport SafetySpecialist with the Federal AviationAdministration’s Airport TechnologyResearch and Development Branch. He isbased at the FAA’s William J. HughesTechnical Centre in Atlantic City NJ, USA,where he manages research projects inVisual Guidance, Aircraft Rescue andFirefighting, Airport Design Safety, andOperation of New Large Aircraft. Jim hasa Bachelor of Science degree in AirportManagement – Flight Technology fromFlorida Tech, Melbourne, Florida, is anactive volunteer firefighter and is also aholder of a Commercial pilot certificateand Certified Flight Instructor Certificate.Jim has worked in Airport SafetyResearch and Development for 14 years.

Figure 1: Example of a mechanics tool laying on a runway

FOD_patterson:Layout 1 19/3/08 12:52 Page 1

TECHNOLOGY l FOD DETECTION

surface, visually looking for anything thatmight be out of the ordinary, including thepresence of FOD. As a backup, the airportoperators may receive reports from pilotsor from air traffic control that a piece ofFOD has been seen on the airport’ssurface. In many cases however, thelocation and type of FOD are givenincorrectly, so the airport operator mayspend a significant amount of timesearching the reported area. Weather,darkness, and traffic are all componentsthat further complicate the airportoperators search for the piece of FOD,thus resulting in what might be viewed asa hasty search; which on many occasions,comes up empty.

It has been estimated that FODdamage costs the aerospace industry over$4 billion (US) per year, mostly in thecosts associated with engine damage andloss of use of the aircraft. FOD damage toaircraft happens all of the time, buttypically does not receive the same level ofattention as an actual accident. The mostnoted FOD related accident takes us backto 25 July 2000, where 100 passengers,nine crew members, and four people onthe ground were killed when Air FranceFlight 4590 crashed after departing fromCharles de Gaulle International Airportnear Paris. The aircraft had run over apiece of titanium debris on the runway,that had fallen from an aircraft that tookoff about four minutes earlier.

Investigators discovered that the piece ofdebris on the runway had shredded a tire,causing the accident. While catastrophicaccidents such at this one, that have beendirectly attributed to FOD, are very few,the FAA has recognised that there is still aneed to address the problem of FOD to atleast minimise damage to aircraft, andmore significantly, to prevent anotheraccident from happening.

The FAA’s Airport Safety Research andDevelopment Sub-Team, located at theWilliam J. Hughes Technical Centre inAtlantic City NJ, are evaluating severalnew technologies for debris detection.These technologies have the capability todetect and report the presence of FOD on

a runway surface, greatly enhancing theairport operators’ ability to locate andremove the debris, before it damages anaircraft or causes flight problems.

Under this research program, the FAAselected four different technologies toparticipate in the evaluation, each ofwhich would be installed at a major USairport for a 12 month evaluation period.Selection criteria were based on an initialcapability presentation by the vendor,prototype demonstration, and their abilityto demonstrate overall maturity of theirsystem. Fully developed systems that wereready to be deployed were the primaryarea of interest, so that the long researchprocess could be initiated immediately.

Due to the very labour intensiveprocess of evaluating the differenttechnologies at four different airports, theFAA looked to their Centre of Excellence(COE) Program for assistance. The COEProgram allows qualifying universities toperform investigative research projectssuch as this, along with the FAA. Thisallows graduate level students to gainexperience working in aviation relatedengineering fields. All of the researchefforts are conducted under the closesupervision of an experienced professor, to ensure consistent, reliable, un-biasedresults. For this particular project, theUniversity of Illinois’ Centre of Excellencein Airport Technology (CEAT) was chosento assist in the execution of the researcheffort for FOD Detection. The Universityof Illinois has an expanse of knowledge inevaluation design, execution, andreporting, along with specific experiencein several airport safety related fields.

The evaluation process, designed bythe FAA and the CEAT, included a multi-step approach that would allowresearchers to challenge each technologyon their ability to consistently detect;sample FOD items, FOD items of differentsize/shape/consistency and finally, theirability to find common FOD items on arunway, just as if they were being operatedin the ‘real world.’ Researchers planned toevaluate each technology through a periodof 12 months, to ensure that sufficientinclement weather conditions werecaptured, including snow events, wherethe technologies will be particularly

www.internationalairportreview.com INTERNATIONAL AIRPORT REVIEW l ISSUE 2 l 2008 23

Figure 2: Collection of FOD items used by researchers in evaluation of detection capabilities

Figure 3: CEAT researcher positions a piece ofFOD for nighttime testing

FOD_patterson:Layout 1 19/3/08 12:52 Page 2

TECHNOLOGY l FOD DETECTION

26 INTERNATIONAL AIRPORT REVIEW l ISSUE 2 l 2008

challenged to differentiate between actualFOD items and accumulating snow.

The four FOD detection systemsselected to participate in this evaluationincluded: a millimetre wave radar system,developed by UK based company QinetiQLtd, a combination radar and highresolution camera system, developed by

the Israeli based company XSight, amobile millimetre wave radar system,developed by a US based company calledTrex Enterprises, and finally, a highresolution intelligent vision system,developed by a Singapore based companycalled Stratech.

Personnel from the CEAT and FAA,regularly travel to each of the fourrespective test locations to conduct theevaluation activities. Initially for the firsttest, a set of calibration targets are placedat pre-selected positions along the runwaysurface. The system is then allowed toscan the runway to look for thecalibration targets. In this test, the generalsystem operation is evaluated to confirmoperational status and consistency in

repeated detection of the calibrationtargets. Month after month, the same targets are placed at the samelocation. The system should demonstraterepeatability from month to month.

In the second test, a standard set ofFOD items (items include pieces of airportsignage, rocks, chunks of pavement

sealant, fuel caps, catering items etc), areplaced on the runway surface at pre-determined positions (See Figure 2 on page23). While the positions of the FOD arerepeated each month, the particular itemof FOD at that spot is randomly changed.For example, a fuel cap at position A1 onthe first month would be switched toposition D3 the next month. Position A1would then have a different item placedon that spot during the next month.

Testing proceeds withrotation/detection cycles, where each itemis rotated in-place approximately 45degrees, to test the systems ability todetect various items of FOD, regardless oftheir orientation to the detection sensor(See Figure 3 on page 23). For example, a

long piece of tubing would have a verybroad detection surface when viewed fromthe side, but would only appear as a smallcircular item if viewed from either of thetwo ends. Rotating each individual itemgives researchers a complete understandingof how the system is able to detect variousitems at various locations, at variousorientations. The detection performance isassessed based on how well the system canfind the FOD items, and how it handlesthe various FOD orientations.

The final test is what researchers call‘blind testing’, where unknown items areplaced at unknown locations on therunway surface. This is the closestresearchers can get to evaluating thesystem in a real world environment, sincethe system will not know where to look,and it won’t know what to look for.Researchers randomly select a series ofFOD items, and place them at variousrandom spots along the runway surface(See Figure 4). The system is then allowedto scan the runway surface, and is gradedon how many items it can find.

Throughout all the tests, weatherconditions, temperatures, FOD items used,locations, and any other pertinentinformation, is recorded and logged into anotebook for further analysis. After thetests are completed, the data is compiledto support preparation of final reporting.

The FAA’s evaluation of FODdetection technologies was initiated inJune of 2007 with the first system,developed by QinetiQ, being broughtonline for evaluation. The QinetiQ system,trade named the Tarsier Radar, wasinstalled at the T F Green Airport (KPVD)in Warwick, in Rhode Island US. Thissystem uses tower-mounted radar unitsthat continuously scan the designatedpavement surfaces to detect FOD. OnceFOD is located, the system generates analarm and gives the user a message,including where and when the FOD itemwas found. This system is very similar tothe QinetiQ system that was installed at the Vancouver International Airport inBritish Columbia, Canada approximatelytwo years ago.

The second system to be broughtonline was the XSight System, tradenamed FODetect, which was installed at

Figure 4: An example of larger piece of FOD being used for blind detection evaluation

Figure 5: XSight’s FODetect Surface Detection Unit in place on the edge of a runway

FOD_patterson:Layout 1 19/3/08 12:53 Page 3

TECHNOLOGY l FOD DETECTION

Boston-Logan Airport (KBOS),Massachusetts US. This system uses smallSurface Detection Units (SDU) thatcontain both radar and camera units thatare mounted near the runway edge, nextto the runway edge lights (See Figure 5 onpage 26). Each SDU scans areas to therunway centre line and upon detection ofFOD, immediately sends an alarm messageto the operator, notifying them of theprecise location of the FOD and the timeit was found. It then zooms in andprovides a video image of the FOD, asseen from the sensor unit. With detection,the sensor locks on the FOD position toassist in retrieval (a laser illuminator isused for night time retrievals). This systemwas brought online in February of 2008.

The third system that will be broughtonline is the Trex Enterprises system, tradenamed the FODFinder. This is a mobiledetection system that can be mounted tothe roof of a vehicle. This system will beevaluated at Chicago’s MidwayInternational Airport (KMDW). Thesystem uses millimetre wave radar that ishoused in an enclosure on the roof of thevehicle (See Figure 6). This system isunique in that it is mobile, so FODdetection is capable not only on runways,but taxiways, apron areas, etc. As thevehicle moves forward, the system scansthe area in front of the vehicle andprovides the operator with both radar andvideo indications of FOD. A movingscreen, based on aerial photography,supports situational awareness. A detectedFOD item is indicated on this screen,providing directions to the operator forretrieval. Once retrieved, the FOD item isphotographed and given an inventorynumber that is printed in a bar code on alabel. This system is due to be online inMarch of 2008.

The fourth system, expected to beinstalled and brought online later in thesummer of 2008, is the Stratech intelligentvision system, called the iFerret FODDetection system. It was recentlyannounced that this system will beinstalled at Singapore’s ChangiInternational Airport. In the US, iFerretwill be installed at Chicago O’HareInternational Airport (KORD). Thissystem uses a high resolution camera

system that visually scans the runwaysurface to detect FOD. Sophisticatedimage processing software adapts tochanging lighting and surface conditions.When FOD is found, the system has thecapability to ‘zoom in’ on the item. Thisprovides the user with an instant image of

the debris, so that the user can see what the system has detected. The system,like the others, also provides the user withprecise location, time of alarm, images ofthe FOD and a continuous log of alarmsthat the system had detected.

The evaluations being conducted foreach of the different technologies, havepresented some interesting challenges that

have required researchers to adjust theirevaluation techniques. For example, theradar based systems do not react tocolour, but the camera based systems, onthe other hand, do react to colour andlighting contrast. Researchers had to addFOD targets with different shades of grey(black, grey, and white) to the evaluationprotocol, so that the camera based systems

could be evaluated on their ability todetect objects that had different levels ofcontrast with their surroundings (SeeFigure 7).

As the evaluations of each technologycontinue, the FAA and the CEAT intend tobegin drafting a final report. This report

will set up the framework required todevelop a performance specification forthese types of systems. This performancespecification is likely to be released as anFAA Advisory Circular (AC). ACs areused by the FAA to inform airports aboutnew technology and to providespecifications for airport related systems,such as visual aids and airport pavementdesign etc.

The evaluation of FOD detectionsystems has prompted internationalinterest, with many other countriesinitiating their own research efforts, manyvery similar to the effort being conductedby the FAA. Eurocontrol in particular, hasinitiated a similar research effort, with thegoal of developing a performance standardthat could potentially be acceptedinternationally through the InternationalCivil Aviation Organisation (ICAO).France has also indicated that they areinvestigating FOD detection systems aswell. The FAA has taken a proactiveapproach to this technology, and is eagerto work on an international level to ensurethe safety of the flying public, bothdomestically and internationally.

Information on the FAA’s AirportTechnology R&D Branch can be found at:http://www.airporttech.tc.faa.gov

www.internationalairportreview.com INTERNATIONAL AIRPORT REVIEW l ISSUE 2 l 2008 27

Figure 6: Mobile FOD Detection Technology developed by Trex Enterprises

Figure 7: FOD targets of different shades usedto evaluate visual detection systems

FOD_patterson:Layout 1 19/3/08 12:53 Page 4