In an imperfect world perfection is not instantly available.
Always expect failures — in systems and humans. Don’t let either kill you. – Jim Wetherbee
Safety is top priority of the global aviation industry. Wildlife hazard management is critical to the safety of operations at airports. The airport size may vary from 500 acres to covering over 5,000 acres depending on factors such as volume of passenger traffic, number of runways, and available facilities. The airport environment provides expanses of semi-natural grasslands, creating favourable ecological habitats often neighbouring heavily urbanised areas. These grasslands along with adjacent water bodies are attractive to a range of animals and birds which are hazardous to aviation. ICAO Doc 9137 Airport Services Manual Part 3 – Wildlife Control and Reduction – 4th ed. provide airport personnel with the information necessary to develop and implement an effective bird/wildlife control measures and organisation for their aerodrome. Airport Council International experts also work with airport team to identify, assess, manage and reduce wildlife hazards to ensure safe aerodrome environment.
Without question, modern airports face many demands but they must promote safety above all else. This poses a challenge as air traffic increases. In this article we will focus on wildlife management at the airport where most of the strikes occur. Out of all the species, there are some which pose the greatest strike hazards. With this blog, I wish to draw attention of pilots, airport managers, biologists, airport and urban planners, students, consultants, businesspeople, and others understand how effective wildlife management at airports contributes to the safety and efficiency of air travel worldwide.
- On 04 Dec 2015, a Dash 8-400, performing flight SG-2458 from Mumbai to Jabalpur (India) with 49 passengers and 4 crew, was landing at Jabalpur at 19:30L (14:00Z). The aircraft struck a herd of boars on the landing roll. The aircraft went off the runway and came to a stop on soft ground with the left main and nose gear collapsed. There were no injuries, the aircraft received substantial damage. Three dead boars were recovered from the runway.
- On 06 Nov 2014, a Boeing 737 aircraft was struck by buffalo at Surat while departing for New Delhi. While departing from runway 04, the aircraft hit a buffalo at speed of 76 Knots. The takeoff was aborted and no passenger or crew injuries were reported. The reason was attributed to buffalo strike during take off roll.
- Similar incidents of these nature were reported earlier, In 2008, a Kingfisher Airlines plane hit a stray dog on the runway at the Bangalore International Airport. The same year, an Air India aircraft hit a Nilgai at Kanpur Airport. In 2009, a Kingfisher flight hit a stray pig at Nagpur airport.
As per the DGCA report, the contributing factors to mammal strike on aircraft were – breaches in boundary wall, wild vegetation growth, open drain and lack of scientific passive and active wildlife management techniques. Ref: https://aaib.gov.in/Reports/2014/Accident/Accepted%20Report%20VT-SGK.pdf
On 18 Dec 2023, Minister of State in the Ministry of CIVIL AVIATION, in a written reply to a question in Upper house presented data on aircraft hit by wildlife and bird strike and brought out that maximum number of strikes occurred during take off and landing phase. From the data presented from 2018 to 31 Oct 2023, it was evident that number of wildlife strike to aircraft has continued to increase over the years. Wildlife strike is a peculiar problem which demands constant assessment and novel methods to tackle the hazard. Ref: https://sansad.in/getFile/annex/262/AU1619.pdf?source=pqars
DGCA India, has implemented various measures to reduce the incidents of wildlife strike on aircraft. Some of them being-
- DGCA has issued regulations and guidelines for management of potential wildlife hazard at licensed airports.
- Aerodrome Advisory Circular AD AC 06 of 2017 has been issued to aerodrome operator for implementing an effective wildlife control mechanism for their aerodrome to control wildlife strike. Civil Aviation Requirement Section 4 Series B Part 1 Para 9.4 mandates aerodrome operator to evaluate wildlife hazard by competent personnel and action to be taken to decrease the risk to aircraft operations by adopting measures to minimize the likelihood of collisions between wildlife and aircraft.
- Further, Aerodrome Advisory Circular AD AC 01 of 2022 has been issued to identify the gaps and ensure strict implementation of plan for wildlife hazard management on and in the vicinity of aerodrome.
- Compliance of the regulation and guidance issued for Wildlife Hazard management is being done through annual surveillance inspections of the aerodrome.
- Rule 91 of The Aircraft Rule 1937 prohibits dumping of garbage and slaughter of animals that may attract wildlife within 10km of Aerodrome Reference Point.
Wildlife strikes (mainly birds, but also includes bats and other mammals on the ground) with aircraft is a serious economic and safety concern in the aviation industry. In India, the pioneering airfeld bird ecological studies were started under the leadership of Dr Salim Ali and Dr RB Grubh of Bombay Natural History Society (BNHS) in 1980. The research team consolidated their study report for 22 airports during the period 1980-1988. As the number of fights increase in the airspace, the problem of their collision with birds (and wildlife in general) will also increase. The solution to the problem can be evolved by identifying the species involved in the incidents/ accidents. In the Indian context, such an attempt was started in1980. In the recent past, the Indian Air Force adopted the DNA Bar-coding technology to identify the species involved.
Actions to Reduce Wildlife (Mammal) Strikes
Although some management activities are considered as common sense and common practice at all airports (e.g., covering trash containers and discouraging the deliberate feeding of wildlife), others are more specific to context, such as the various types of vegetation management. Care should always be taken that the elimination of one species does not inadvertently create an attractant for another, more hazardous species. A strategy or tool at one location may be successful while fail miserably at another. No one plan will be successfully in every location for every species; therefore an approach that combines techniques in an integrated fashion is most effective.
- Birds accounted for 97 % of wildlife incidents.
- 87 % of bird incidents do not cause damage to aircraft.
- Terrestrial mammals represent only 2 to 3 % of wildlife incidents.
- 59 % of Mammal strike incidents caused damage to aircraft.
- Mammal strike incidents were reported during dusk and early night time.
- More than half the aircraft destroyed in wildlife incident were damaged by mammals.
- Mammal incident are almost five time more likely to incur damage than all other wildlife.
- Mammal strikes are more likely to occur during landing roll.
Animal movement may be attributed to species breeding seasonality and daily activity. Understanding relationships between animal behavioural traits and temporal distributions can be used to better understand wildlife-aircraft collision risk assessment. Airport mangers should establish a “zero tolerance” policy for mammals within aircraft operating areas. However, animal/mammal management can be complex and each airport has unique features. Therefore, airport managers should request help from professional wildlife biologists trained in wildlife damage control to assess hazards and provide recommendations.
There are four basic management practices available to minimise mammal strike are :
- Exclusion – The most secure protection against mammal hazards is total exclusion with fencing done in conjunction with population removal. The fence should be 2.4 m high preferably 3.0 m with an additional three strands of barbed wire on top. Fences must be maintained so there are no gaps along the ground or at entry gates. Cattle guards are effective in keeping cattle from entering through gates that must be left open at times.
- Population removal – Population removal requires close cooperation with state wildlife agencies for permits and approved methods. The safest and most humane removal technique is capture and relocation.
- Habitat management – Habitat management includes removing wooded and brushy areas adjacent to runways. Although more research is needed to study the effect to eco system in general.
- Harassment – Harassment techniques can include pyrotechnics (fireworks), sirens, propane exploders, flashing lights, and vehicles. Though animals are known to adopt to these devices within a few days. Harassment can be effective if selectively used immediately prior to aircraft takoffs and landings. Increased diligence in harassment is needed especially including no single technique is 100% effective.
The best approach to reduce mammal strike to aircraft would be mix of long, mid and short term techniques and to integrate several methods into a comprehensive wildlife management plan that is periodically evaluated and updated. Mammal aircraft strike is a global issue. Different geographical locations have different species and pose divergent threats to aircraft strike. A more thorough understanding of the ecology of mammal groups inhabiting and using airfield is required to maximise the efficacy of mitigating measures. Reporting of wildlife strike should be made mandatory as it is estimated that these are highly under reported. Focusing on reporting of timely and accurate data is important to study the risk, knowledge synthesis and development of management procedures.
Be Safe. Happy Landings.
Reference:
- Behavioral Traits and Airport Type Affect Mammal Incidents with U.S. Civil Aircraft, Schwarz et al, USDA National Wildlife Research Center – Staff Publications. 1544., https://digitalcommons.unl.edu/icwdm_usdanwrc/1544
- Runway roadkill: a global review of mammal strikes with aircraft.
