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25 Clearly, a critical aspect of any successful FOD manage- ment program includes the actual removal of debris from the AOA. This involves removing FOD as expeditiously as pos- sible without undue interference of airport operations, all the while considering the safety of the individual responsible for removing debris. In developing a FOD removal plan, airports may wish to consider: â¢ Implementing a policy that conveys whom, when, how, and with what equipment the removal of FOD shall take place. â¢ The risk assessment process in FOD removal; especially, how this can be complimentary to an SMS plan. â¢ Implementation with sensitivity to the risk, traffic, and safety of everyone on the airport. The removal process can range from being fairly simple and straightforward to very complex and dangerous. For exam- ple, a luggage tag that finds its way on the apron surface can be immediately removed by the line crew, whereas a piece of metal that finds its way onto the runway, is another situation altogether. Furthermore, wildlife FOD may be removed by personnel different than the personnel that removes other types of debris, as a result of the oftentimes biohazard nature of wildlife FOD. It is the duty of the airport operator to ensure that this part of the process is conducted in the most profes- sional and conscientious way possible, considering aircraft traffic and the location of FOD. Although each airline or tenant can be asked to keep their area free from FOD, it is ultimately the responsibility of the airport operator to mitigate FOD. To accomplish this, air- ports may adopt manual, as well as mechanized, equipment removal. The most successful means for removing such debris is with FOD removal equipment. This equipment is available commercially and can be used in conjunction with manual removal methods. At the same time, however, the use of FOD removal equipment may lead to complacency. This may occur because the employee considers the equipment as the primary tool for FOD removal, relying on it too heavily, and becoming less engaged in the FOD removal process (see Figure 12). CURRENT EQUIPMENT AVAILABLE FOR REMOVAL Removal Continuum A number of solutions exist for the removal of FODâranging from non-mechanized to mechanized. The continuum in Fig- ure 13 has been developed to present the range of options available to airports. Non-mechanized FOD Removal Of the two main types of FOD removal equipment, those cat- egorized as non-mechanized are simply attached to, or towed behind, a vehicle. These non-mechanized units are fairly versatile, with the ability to be attached to a tug, airport oper- ations vehicle, or maintenance truck. Because they are non- mechanized, they are less costly to operate and rarely out of service as a result of mechanical issues. Tow-behind Friction Mats Within the non-mechanized category, there are several types of equipment. First, tow-behind friction mats utilize a series of bristle brushes and friction to sweep FOD into sets of capture scoops, which are covered by a retaining mesh to hold the collected debris. Figure 14 shows a tow-behind friction mat. Magnetic Bars Magnetic bars are another non-mechanized piece of equip- ment available to airports for removing FOD. These bars are attached to vehicles and designed to collect metallic debris. With the majority of FOD collected at airports being metal, this piece of equipment is a simple solution to that specific FOD source. To ensure effectiveness, airports uti- lizing magnetic bars inspect and clean the bars regularly to remove all accumulated metallic debris. If not, once col- lected, debris may fall off the vehicle and become FOD yet again. Figure 15 shows a magnetic bar attached to the front of a pick-up truck. CHAPTER FOUR REMOVAL
Rumble Strips Rumble strips, or FOD shakers, are the third type of non- mechanical equipment available for FOD removal. This system is comprised of 10- to 15-ft-long devices positioned on the pavement to dislodge FOD from vehicles as they are driven over. Rumble strips can typically be moved as needed. According to Drew Lasseter, Guantanamo Bay Airfield Facil- ity Manager: FOD shakers will not remove all FOD from tires. In many cases, it removes FOD, but in just as many cases it loosens it up enough that it becomes likely that the FOD will fly off while on the ramp. FOD shakers are never a substitute for human interaction (Peck 2010). Additionally, in northern climates, the freeze/thaw cycle may degrade some types of rumble strips, thus creating FOD. Although once quite common, these devices are no longer a widely accepted FOD removal system. A better practice is for 26 the operator to stop a vehicle at a designated checkpoint, per- form a visual inspection for debris on the vehicle, and use a hand tool to manually remove debris from tires or undercar- riages. Figure 16 shows rumble strips in use on an asphalt road. Mechanized Foreign Object Debris Removal Mechanized FOD removal can be more costly for an airport; however, many times the additional expense is justified by the enhanced efficiency provided by a mechanized unit. Proper maintenance is necessary to ensure successful operation with minimal breakdown of equipment. Power Sweepers Power sweepers, which include tow-behind bristle trailers, first remove debris from the pavement. A true mechanical broom sweeper can clean the surface of large debris, but dirt FIGURE 12 FOD removed during one FOD walk at Kadena Air Base, Japan. (Source: U.S. Air Force photo/Airman 1st Class Jarvie Wallace.) FIGURE 14 Tow-behind friction mat. Source: Sherwin Industries. FIGURE 13 Continuum of equipment available for removal.
27 and fine particulates may be remain on the surface and in pavement cracks. These units are typically used throughout the airfield on pavement surfaces, as well as on ramp areas where ground support equipment is staged. According to AC 150/5210-24, bristles can detach from brooms and become a source of FOD (FAA 2010a). Therefore, metal bristles or spines should not be used for FOD removal purposes. Plastic or combination plastic/metal bristles may be appropriate for airports depending on the equipment manufacturer recom- mendations. Regardless of the equipment used, a thorough visual check of the pavement should be conducted at the con- clusion of the sweeping procedure (FAA 2010a). Figure 17 shows a self-propelled, walk-behind sweeper, while Figure 18 shows a sweeper attached to a tractor. Figure 19 shows a sweeper truck. FIGURE 15 Magnetic bar. Source: The F.O.D. Control Corporation. FIGURE 17 Self-propelled, walk-behind sweeper. Source: Digital Commons. FIGURE 18 Sweeper attachment. Source: Digital Commons. FIGURE 16 Rumble strips. Source: A.J. Broom Road Products. FIGURE 19 Sweeper truck. Source: Digital Commons.
Vacuum Systems Next, vacuum systems rely on air flow as the primary means of removing FOD. Although a unit may only contain a vacuum, which may be walk-behind (Figure 20) or driven (Figure 21), airports often utilize a unit that combines a vacuum system with a mechanical broom and/or a regenerative or recirculating air feature (Figure 22). By utilizing a constantly moving windrow broom to transfer debris over to a suction nozzle at one side of the sweeper, debris are removed by means of a suction tube. Jet Air Blowers The final option in using mechanized equipment to remove FOD is with jet air blowers. These systems direct a stream 28 FIGURE 21 Vacuum truck. Source: Tymco. FIGURE 23 Jet air blower. Source: RPM Tech. FIGURE 22 Vacuum with mechanical broom and regenerative air feature. Source: Tymco. FIGURE 20 Walk-behind vacuum. Source: Mid Carolina Turf and Outdoor Equipment. of high velocity air toward the pavement surface. Techni- cally, these systems do not remove FOD, they simply dis- place it. Although a jet air blower may not contain a debris collection mechanism, it is beneficial to only acquire jet air blowers that incorporate a debris collection mechanism to avoid blowing FOD to other areas. One jet air blower cur- rently on the market is capable of blasting ambient air with speeds of up to 438 mph. The manufacturer states that this is effective in removing ice, dirt, snow, leaves, and other debris (see Figure 23). Foreign Object Debris Storage Lastly, although not categorized as FOD removal equipment, containers for the purpose of storing collected FOD are bene- ficial for a FOD management program and the final step in the removal process. By ensuring that storage systems or FOD containers are easily seen and visible from all gates for the pur- pose of gathering debris, as well as marked appropriately and emptied regularly to guard against any overflow, the contain- ers are more likely to be used. The FAA also suggests that airport employees wear âpouchesâ to collect any debris they might come in contact with while conducting their respective duties. Although five-gallon buckets are common at many air- ports, the FAA recommends that FOD containers have covers
29 or lids to prevent wind or jet- or prop-wash from stirring up or shifting debris inside the container, thus creating more FOD (FAA 2010a). It is helpful to locate FOD containers in all high traffic areas, generally near entry points to the AOA, hangers, maintenance areas, FBO, and at each aircraft gate. If there are multiple containers in visible locations, personnel will be more apt to properly dispose of FOD without being prompted. For hazardous materials, specialized containers, in accordance with appropriate regulations, must be used. Figure 24 shows an example of FOD containers. CURRENT AIRPORT REMOVAL PRACTICES Common Foreign Object Debris Types To determine the most common types of debris removed at air- ports, this synthesis queried the airports. Airports were also asked to indicate the most common types of FOD removed by area. Findings suggest that certain types of FOD (such as plas- tic and/or polyethylene materials) are generally quite common throughout the airport environment. Other types of FOD (such as flight line items) are most common only in specific areas (such as flight line items on air carrier ramps). As seen in Table 3, the data can be reduced to the four most common types of FOD removed by area. Movement areas (runways and taxiways) share the first and second most com- mon types of FOD (runway and taxiway materials, and natural materials, respectively). Aircraft parts and debris resulting from winter operations are also commonly found along run- FIGURE 24 FOD containers. Source: San Antonio Airport System. Area First Most Common Second Most Common Third Most Common Fourth Most Common Runways Runway and taxiway materials Natural materials Aircraft parts Winter ops Taxiways Runway and taxiway materials Natural materials Winter ops Aircraft parts Taxi Lanes Winter ops Runway and taxiway materials Apron items (tie) and natural materials (tie) Aircraft parts (tie) and plastic and/or polyethylene materials (tie) Air Carrier Ramps Apron items Flight line items Winter ops Aircraft parts Cargo Ramps Apron items Winter ops Plastic and/or polyethylene Aircraft parts (tie) and flight line items (tie) GA Ramps Apron items Winter ops Flight line items Plastic and/or polyethylene (tie) and natural materials (tie) Hangar Areas Aircraft parts Winter ops Mechanicâs tools Apron items (tie) and construction debris (tie) and plastic and/or polyethylene (tie) Outside Defined Construction Areas Construction debris Plastic and/or polyethylene Apron items Natural materials Nonpavement Areas Plastic and/or polyethylene Apron items Natural materials Construction debris TABLE 3 FOUR MOST COMMON TYPES OF FOD REMOVED BY AREA
30 83% 74% 55% 31% 21% 12% Power sweeper, including tow-behind bristle trailer Vacuum systen Magnetic bars Jet air blower Tow-behind debris retention mesh Rumble strips FIGURE 25 Types of FOD removal equipment in use. Note: Participants were asked to select all that apply. Thus, percentages do not total 100%. ways and taxiways. Similarities in FOD types also exist among non-movement areas. For instance, apron items (such as paper debris, luggage parts, and debris from ramp equipment) are the most common type of FOD found on ramps (including air carrier, cargo, and GA). FOD as a result of winter operations (such as ice and snow, vehicle or equipment parts, and broken lights) are also quite common among non-movement areas. Common Removal Methods In practice there are only two main methods available to remove FOD from airport surfaces. First, airports typically manually remove debris by physically picking it up, whether by hand or with a shovel or other device. Second, debris can be removed with the use of mechanized equipment, whether by a sweeper, vacuum, magnetic bar, or other piece of equipment. To understand the degree to which airports rely on these vari- ous methods of removing FOD, airports were queried as to the methods they use. Fully 100% of participating airports remove FOD manually (or by human means). However, 91.5% also remove FOD mechanically using some sort of equipment designed for such purpose. Furthermore, 15% of participating airports have plans to acquire additional equipment for remov- ing FOD within the next 24 months. Common Foreign Object Debris Removal Equipment Those airports using some sort of FOD removal equipment were asked about the specific types in use. Figure 25 reveals that the most common type of equipment in use is the power sweeper. One airport also indicated that they have a dust pan attachment to their sweeper. A vacuum set-up is also quite common, with magnetic bars also used by more than half of participating airports. Less common are jet air blowers, tow- behind retention mesh, and rumble strips. Based on the most common type of FOD found at an air- port, and the area in which each type is found, it is helpful to conduct a risk assessment to determine the hazards presented by the FOD and then adopt tools to mitigate those hazards. For instance, if metal debris are found on runways, the airport may wish to install magnetic bars on all operations and mainte- nance vehicles. If vegetation is a problem on taxiways, main- tenance personnel may need to pay closer attention to mowing practices, and use power weepers and/or vacuum systems after each mowing event. Of those airports using some type of technology or equipment for removing FOD, 79% indicated that this equipment is very useful at removing FOD. Of those indi- cating the technology or equipment was very useful, the vast majority (91%) are using a power sweeper. A great number are also using a vacuum system (73%) and mag- netic bars (61%). Somewhat less common are jet air blow- ers (40%) and tow-behind debris retention mesh (21%). Only 21% of participating airports indicate the equipment is somewhat useful, whereas no airports indicated that it was not useful at all.