Recommended Practices No. 1
Standards For Aerodrome
Several excellent handbooks exist that describe in detail the techniques that can be used to manage the bird/wildlife strike risk on aerodromes (e.g. ACI 2005, CAA 1998, Cleary & Dolbeer 1999, Transport Canada 2001). There has, however, been little attempt to determine the levels of investment in time, manpower, equipment, training and monitoring that are needed to effectively manage the bird/wildlife hazard. This contrasts with other aerodrome safety provisions, such as levels of fire control equipment and manpower, that are precisely defined by regulation. This situation has arisen, in part, because the levels of risk, the habitat type, and the bird/wildlife species present at different aerodromes varies, and the precise techniques that are successful at one site may not work at another. It is also partly due to differences in the levels of resources available at different airports and to differences in the attitude of airport managers and national regulators to the risk posed by bird/wildlife strikes.
The new International Civil Aviation Organisation Standards And Recommended Practices (SARPS) on airport bird/wildlife control became effective in November 2003. The guidance material accompanying the SARPS is in the process of being updated. This guidance will, when combined with the various manuals listed above, provide the technical detail needed to construct a bird/wildlife control programme. It does not, however, describe the levels of effort that are needed if a bird control programme is to operate effectively. It was therefore agreed at the 26th meeting of IBSC in Warsaw that a set of IBSC standards should be developed by the committee to address this issue.
This paper seeks to identify those areas where universally applicable practices can be identified, and suggests levels of airfield habitat management, bird control equipment, manpower, etc. that, in the opinion of the IBSC membership, an airport should have in place if it is to effectively manage the birdstrike risk to aircraft. It is envisaged that these standards will inform airport managers, national regulators, the insurance industry, lawyers etc. about what they should expect to see invested in bird/wildlife control at an airport. Airports with unusually high bird/wildlife strike risk for whatever reason would be expected to invest more in strike prevention than is described below in order to reduce that risk.
There are clearly many private aerodromes that are too small to justify the provision of bird/wildlife control to the levels described in this document. However, in the opinion of IBSC, these standards should apply to any aerodrome carrying regularly scheduled commercial air traffic, irrespective of the movement frequency or type of aircraft involved.
No attempt has been made to provide a detailed scientific underpinning for the best practices proposed. Those wishing to explore the underlying science in more depth are referred to previous volumes of the proceedings of IBSC ( http://www.int-birdstrike.com ), Birdstrike Committee Europe, Birdstrike Committee N. America (www.birdstrike.org and http://www.birdstrikecanada.com), German Birdstrike Committee ( http://www.davvl.de ), and the scientific literature. The aim of this document is to distill collective experience of ornithological and aviation experts into a set of basic standards that the aviation industry as a whole can use.
1. Airfield Habitat Management
Controlling the attractiveness of an airport to birds and other wildlife is fundamental to good bird control. Indeed, it is probably more important than bird dispersal in terms of controlling the overall risk. If an airport provides easily accessible resources to birds/wildlife in terms of food, water, shelter or breeding sites, then they will continue to try and return despite any dispersal tactics that are used to dissuade them. The control programme is thus doomed to failure unless the airport is made as unattractive to birds/wildlife as possible. Habitat management to deter birds/wildlife involves two processes, identifying the attractive features and implementing changes to either remove the attraction or to deny access to it.
A named member of the senior management team at the airport should beresponsible for the implementation of the bird control programme,including both habitat management and active bird control.
The reasons why birds frequent an airfield are not always obvious. They may be attracted to food such as invertebrates, small mammals, seeds or plants in the grassland; water from ponds, ditches, or puddles on the tarmac, nesting sites in trees, bushes or buildings, or simply the security offered by large open spaces where they can easily see approaching predators. In some cases it may be obvious what resources they are attracted to, but in others it may not. If there is any uncertainty, obtaining the assistance of a professional bird/wildlife prevention specialist is advisable in order to identify what it is that is attracting the birds/wildlife to the airefield. Obviously, the attraction will vary from one species to another.
Once the attraction has been identified, a management plan should be developed either to remove it entirely, reduce it in quantity, or to deny access to it. Because airfields around the world are all different and because the bird/wildlife species that frequent them vary from region to region, it is not possible to define precisely what types of habitat management will be effective at a particular site. Typical examples include manipulating the species and/or height of vegetation cover on the airport, removal of trees and bushes, netting of water bodies, excluding birds from buildings by netting or other means, selection of non-attractive amenity planting around terminals etc.. Whatever techniques are used, all airports should be able to show that they have assessed the bird attractions on their property and developed and implemented a habitat management plan to reduce these attractions as far as is practicable
An airport should undertake a review of the features on its property thatattract hazardous birds/wildlife. The precise nature of the resource that thethey are attracted to should be identified and a management plan developedto eliminate or reduce the quantity of that resource, or to deny birds accessto it as far as is practicableWhere necessary, support from a professional bird/wildlife strike preventionspecialist should be sought.
Documentary evidence of this process, its implementation and outcomesshould be kept.
A properly trained and equippedbird/wildlife controller should be presenton the airfield for at least 15 minutes prior to any aircraft departure orarrival. Thus, if aircraft are landing or taking of at intervals of less than 15minutes there should be a continuous presence on the airfield throughoutdaylight hours. The controller should not be required to undertake anyduties other than bird control during this time. Note that for aerodromeswith infrequent aircraft movements, 15 minutes may not be long enough todisperse all hazardous birds/wildlife from the vicinity of the runway. In thiscase the controller should be deployed sufficiently in advance of the aircraftmovement to allow full dispersal to be achieved.
At night, active runways and taxiways should be checked for the presenceof birds/wildlife at regular intervals and the dispersal action taken asneeded. 9
Whichever organisational system is in place, it should deliver the standards described elsewhere in this document.
Communication between the various interested gropus and organisations on an airport is essential if good bird/wildlife control standards are to be achieved. Airfield Operations, Grounds Maintenance, Air Traffic Control, Airport Fire Service, Airport Planners, Airlines etc. All have a role to play in identifying and correcting problems that may occur. Airport management should ensure that a mechanism is available (e.g. an airport birdstrike prevention committee) which enables these organisations to participate in the bird/wildlife hazard management process. This will help to ensure that these organisations
Bird/wildlife deterrent devices can be broadly divided into visual, acoustic and lethal, and subdivided into portable and static systems. The levels of sophistication, and hence cost, available are highly variable and include the simple scarecrow, (a static visual device), complex radio controlled sound grenerators (static acoustic), pyrotechnic pistols and vehicle mounted distress call apparatus (mobile acoustic), hand held lasers (mobile visual), traps (static lethal) and a shotgun (mobile lethal). The choice of which systems, or combination of systems, to deploy will depend on cost, legal and logistical constraints and, perhaps most importantly, on the species 10
that need to be dispersed. For example, attempting to use a distress call system on a bird species which do not produce such calls is doomed to failure.
Relatively few of the bird/wildlife control devices available to airports have been subjected to a proper scientific evaluation of their effectiveness. It is not possible, therefore, to recommend particular devices as being suitable for bird control at every airport.
Portable equipment, that requires a staff member on the airfield to operate it, is generally regarded as offering the best control, providing that the staff involved are properly trained and motivated. Devices such as pyrotechnic pistols, or vehicle mounted distress call generators produce an impression of a direct threat which can be continually varied in time and location by the operator in a manner not available to static systems. In all cases staff should have access to a shotgun to remove birds/wildlife that cannot be dispersed by non-lethal means, providing that the relevant bird protection and firearms legislation in the country concerned permits this. It is vital that staff are properly trained in the safe use of firearms and carry the necessary permits to own or operate the weapon. There is some debate as to the necessity of the use of lethal control in aerodrome bird/wildlife management, but the view of the vast majority of experts is that supporting the non-lethal threat of pyrotechnic and other devices with an element of lethal control is important because it helps to ensure that birds/wildlife do not habituate to the control programme and permits the selective removal of any birds/wildlife that fail to respond to the dispersal techniques deployed.
In general, static bird scaring devices, such as gas cannons or other sound generators, gradually lose their effectiveness over time. Although some of the more sophisticated devices, which generate a variety of sounds in random or pre-programmed order, may delay this habituation, they are generally more suitable for providing short term bird deterrence from limited areas (e.g. ground being reinstated after building works).
Trained predators (falcons and dogs)
Trained falcons and dogs, which are both potential predators for many species of hazardous birds found on airports, are undobtedly effective in dispersing birds. To work properly, however, considerable investment in the training of both the animals and their handlers needs to be made. This training is essential both to ensure that the animals themselves do not become a strike risk and also to ensure that the deterrent value of deploying the falcon or dog is maximised. Airports should not underestimate the staff time and cost involved in incorporating falcons or dogs in their bird control programmes. It is also important to remember that falcons and dogs are not effective at dispersing all hazardous birds in all conditions. They should be regarded as one tool amongst many that the bird controller can use. The use of trained predators alone is not an adequate substitute for the other bird management techniques described above.
Bird control staff should be equipped with bird deterrent devices appropriate to the bird species encountered, the numbers of birds present,and to the area that they need to control. Staff should have access toappropriate devices for removal of birds/wildlife, such as firearms or traps,or the means of calling on expert support to supply these techniques atshort notice.
All staff should receive proper training in the use of bird control devices.
Airport bird/wildlife controllers should record the following at least every 30minutes (if air traffic is sufficiently infrequent that bird patrols are more than30 minutes apart, an entry should be made for each patrol carried out).
• areas of the airport patrolled,
• numbers, location and species of birds/wildlife seen,
• action taken to disperse the birds/wildlife,
• results of the action.
More general information such as the name of the bird controller on duty,time on and off duty, weather conditions etc should be recorded at the startof a duty period.
6. Birdstrike Reporting
All bird/wildlife management programmes need to be monitored to see if they are working effectively and whether they need to be modified, extended or improved. The only effective way to do this is by collating data on the strikes at the airport concerned. Other measures, counting the birds/wildlife on the airfield for instance, provide useful additional information, but are not a direct measure of the strike risk at the airport. All strikes should be reported, whether or not they cause damage to the aircraft and whatever bird/wildlife species was involved. Unless the airport is confident that it knows what species are being struck on its property it cannot hope to target its management efforts in the correct direction. It is important that airport managers do not penalise staff for reporting birdstrikes. Even though strikes to large jet airliners from small species such as swallows or sparrow-sized birds are unlikely to cause damage to an aircraft, staff should be required to report them. Similarly, the total number of strikes at an airport should never be used as a measure of strike risk or of the performance of the bird/wildife controllers. The main risk arises from strikes with large species, especially birds that form flocks. A risk assessment process that combines strike frequency with likely severity needs to be employed to properly assess the risk (see below). Such a process cannot work effectively unless all strike are reported, however.
There are a wide variety of definitions of precisely what constitutes a bird/wildlife strike. In terms of gathering information to better understand the risk, it is preferable to include as many events as possible in an inclusive definition. Including all strike reports in an airport’s dataset does raise a number of problems, however. For example, if a pilot reports a strike on approach to the airport and a check of the area for a carcass and inspection of the aircraft shows no evidence that a strike has taken place there is no confirmation that a strike has actually occured. Other than the location of the possible strike, such a report provides little useful information (e.g. bird species numbers damage levels etc.) that can aid the airport in targetting its bird control effort. These unconfirmed strikes should be recorded, but do not need to be subjected to the analysis described in 2.7 below.
A number of countries also record near misses in their bird/wildlife strike databases. The definition of a near miss is more problematic as it involves the pilot’s interpretation of how close the birds/wildlife was to the aeroplane and whether this constituted a threat to safety. Also, at airports situated in areas of high bird populations it might be difficult for an observant pilot to land or take off without seeing a bird at some distance from the aircraft and every movement might be regarded as a near miss. Accumulating near miss information may prove valuable, but, like unconfirmed strikes, they should not be included in the airport’s strike statistics used for analysis. Databases etc.should be set up to allow unconfirmed strikes and near misses to be separated from other bird/wildlife strikes when evaluating the dataset.
There are, however, some incidents where a strike does not occur, such as pilots being forced to take evasive action to avoid birds or wildlife, that should be recorded separately as these actions themselves are potentially dangerous and have been caused by the presence of birds.
• Any reported collision between a bird or other wildlife and an aircraftfor which evidence in the form of a carcass, remains or damage to theaircraft is found.
• Any bird/wildlife found dead on an airfield where there is no otherobvious cause of death (e.g. struck by a car, flew into a window etc.).
• Any reported collision between a bird or other wildlife and an aircraftfor which no physical evidence is found.
• Incidents where the presence of birds/wildlife on or around theairfield has any effect on a flight whether or not evidence of a strikecan be found.
Depending upon the organisational structure in a particular country or at an individual airport, the responsibility for reporting bird/wildlife strikes may lie with a number of different individuals or departments, such as airport operations, air traffic control or pilots. It is important that the airport has a mechanism for ensuring that it is aware, as far as is possible, of all of the strikes that happen on or near its property.
7. Analysis of birdstrike data
Effective analysis of birdstrike data is particularly important. For example, separating strikes that occur on the airport (under 200 feet on approach and 500 feet on climb out using the ICAO definition) from those that occur further out in the approaches helps to define those strikes that are likely to be influenced by the airport bird management programme. Similarly, separating strikes with species that are over 100g in weight (i.e. those more likely to cause damage), and giving greater emphasis to strikes with flocks all help to identify trends in the real birdstrike risk at the airport. So, for example, an airport with an increasing rate of bird/wildlife strikes is not necessarily becoming a more risky place to fly. If the increase in strikes is due to an increase in incidents with small species, whilst the rate of strikes with large species and flocks is falling, then this is indicative of both better bird/wildlife control and better reporting of strikes. Again it is important to emphasise that the simple total number of strikes at an airport is not a good indicator of risk, and that examination of the data by species struck is essential. This process can be carried out as part of a formal risk assessment process as described in Section 11, page 17.
Even tiny feather fragments or bloodstains can be idenfified miscroscopically or by DNA analysis.
Airports should establish a mechanism to ensure that they are informed ofall bird/wildlife strikes reported on or near their property.
The total number of birdstrikes should never be used as a measure of riskor of the performance of the bird control measures at an airport.
Airports should ensure that the identification of the species involved inbirdstrikes is as complete as possible.
Airports should record all birdstrikes and include, as far as they are able,the data required for the standard ICAO reporting form
National Regulators should collate birdstrike data and submit this to ICAOannually.
Airports should conduct a formal risk assessment of their birdstrike situation and use the results to help target their bird management measures and to monitor their effectiveness. Risk assessments should be updated at regular intervals, preferably annually.
The appropriate authority shall take action to eliminate or to prevent the establishment of garbage disposal dumps or any such other source attracting bird activity on, or in the vicinity of, an aerodrome unless an appropriate aeronautical study indicates that they are unlikely to create conditions conducive to a bird hazard problem.
Whilst the reference to garbage dumps is clear, ‘any such other source attracting bird activity’ requires a significant degree of interpretation. As with the bird/wildlife attractions on the aerodrome, airport managers may need to seek assistance form specialists when identifying the major bird/wildlife attractions near their airport. They will certainly require some assistance in assessing whether the birds/wildlife using such a site pose a significant risk to flight safety, as this needs an understanding of ecology and behaviour that is unlikely to be available from within the airport’s own staff.
Once sites that support birds/wildlife that are, or might, cause a flight safety problem are identified, management options can be developed. These can range from minor habitat modification, changing cropping or other agricultural practices, major drainage operations or large scale removal of bird/wildlife populations. Again the choice of technique will depend on the particular situation encountered and expert advice should be sought if necessary. Larger scale off-airport bird/wildlife management may also involve liaison with local conservation interests, especially if the sites that need to be managed are nature reserves. In some cases it may be impossible to resolve the conflicting interests of flight safety and conservation, but in trying to do so the airport will be in a better position to show due diligence in the event of an accident or legal claim in the future.
Airports should conduct an inventory of bird attracting sites within the ICAOdefined 13km bird circle, paying particular attention to sites close to theairfield and the approach and departure corridors. A basic risk assessmentshould be carried out to determine whether the movement patterns ofbirds/wildlife attracted to these sites means that they cause, or may cause, arisk to air traffic. If this is the case, options for bird management at the site(s)concerned should be developed and a more detailed risk assessmentperformed to determine if it is possible and/or cost effective to implementmanagement processes at the site(s) concerned. This process should berepeated annually to identify new sites or changes in the risk levels producedby existing sites.
Where national laws permit, airports, or airport authorities, should seek to have an input into planning decisions and land use practices within the 13km bird circle for any development that may attract significant numbers of hazardous birds/wildlife. Such developments should be subjected to a similar risk assessment process as described above and changes sought, or the proposal opposed, if a significant increase in birdstrike risk is likely to result.
ACI (2005), Aerodrome Bird Hazard Prevention and Wildlife Management Handbook
First Edition. Airports Council International, Geneva.
CAA. (1998). CAP 680 Bird Control On Aerodromes. Civil Aviation Authority, London.
Cleary, E.C. & Dolbeer, R.A. (1999) Wildlife hazard management at airports, a manual for airport personnel. Us Federal Aviation Administration, Washington DC.
Transport Canada (2001) Sharing The Skys – An Aviation Guide To The Management Of Wildlife Hazards. Transport Canada, Ottawa.