Birdstrikes – Relying on a Second Miracle?

Nick Yearwood, UK Civil Aviation Authority and Chair of the UK Birdstrike Committee examines a vital safety issue

birdstrike-imageIt is mid March 2013, barely four years since the much publicised birdstrike to US Airways Flight 1549 ‘Miracle on the Hudson’, only this time it is a UK carrier operating a modern twin engine wide body commercial passenger aircraft, taking off from a popular US holiday destination, at night, with more than 300 passengers and 12 crew onboard. The aircraft, en route back to the UK, suffers a multiple birdstrike shortly after takeoff. The impact caused significant damage to both aircraft engines and the airframe. Realising one engine was actually disabled, the crew called a Mayday and returned to land the aircraft safely. On another day, with different parameters, this occurrence could quite possibly have ended in a much worse outcome, highlighting the ever present risk birds pose to aviation.

If nothing else, the incident to US Airways 1549 back in 2009 raised the public consciousness of the birdstrike phenomena. The incident filled the front pages of the world’s newspapers and became the trigger for regulatory safety agencies, operators and the media to focus attention on birdstrikes and the safety risk posed to aircraft flight operations. However, despite all the activity in the wake of the event, has anything really changed, or are we all simply hoping for a second ‘miracle’?

According to the US Federal Aviation Administration (FAA), the risk of birdstrike collisions remains ‘unacceptably high’. The FAA said that the next time an incident involving birdstrikes occurs, airlines, passengers and crew may not be so fortunate. Furthermore, the FAA Inspector General’s office recently warned that not enough was being done to reduce the risk of commercial jets colliding with wildlife near airports and said it was now taking steps to reduce the risk of such collisions.

Turning closer to home, is there a similar belief that more could be done, and, are stakeholders cognisant of the risk posed by off-airport bird and wildlife activities?

There are many technical, risk and data driven questions one might pose in relation to birdstrikes. However, more generally, is there a joined up approach to birdstrikes, enabled by a mature Safety Management System embedded into stakeholder’s organisational safety and operational cultures? Do the global and regional rule makers truly understand birdstrike issues and have they proposed new or tighter regulations and oversight of operators? Does development of new larger ‘next gen’ aircraft demand more resilient certification specifications, and is there any move towards global mandatory birdstrike reporting using harmonised recording system platforms?


In the UK, where mandatory birdstrike reporting has been implemented for 10 years, the CAA now records around 2,500 birdstrikes per year, a number that has more than doubled in the past 15 years, whereas in the US (still without mandatory reporting) in 2011, over 10,000 wildlife strikes were reported.

A study by EASA in 2008 concluded that 95 per cent of all birdstrike occurrences occur below 2,500ft and around 70 per cent occur below 200ft. Various sources quote different percentages for each altitude threshold of strikes, but they all concur that most birdstrike occurrences take place very close to the ground, typically under 500ft and during the take-off phase of flight. This highlights that the risk of birdstrikes is largely influenced, managed, mitigated or eradicated by the effectiveness of measures implemented by an airport operator.

When studying airport related birdstrike data, the UK CAA’s view, and one largely accepted by mature regulators and aviation stakeholders, is that the pure number of bird/wildlife strikes reported at a particular airport does not necessarily imply a greater hazard, although increasingly it is this metric which is referred to, and potentially erroneously relied upon, to indicate the birdstrike risk. The CAA therefore recommends caution be exercised when drawing conclusions from basic numerical birdstrike numbers when determining airport birdstrike ‘league tables’ or when benchmarking airport X vs airport Y. Such league tables are not only counterproductive, but potentially misleading, masking the true risk picture, which requires specialist ornithological and scientific analysis of accurate, reliable and complete birdstrike datum.


From laser scaring devices; long range acoustic and ultra sonic devices; flashing lights; ultra violet paints; synthetic grasses; model aircraft painted like raptors; to gas canisters; falcons; collie dogs; and beyond, there are a myriad of acme birdstrike solutions ‘snake oil salesman’ will try and sell airports purporting to be the cutting edge technological answer to solving the birdstrike problem. Sadly however, many such solutions remain unproven and ineffective, with many lacking even basic data, based on scientifically peer reviewed research or trials. The reality is that there really is no ‘silver bullet’ solution that categorically eradicates the birdstrike risk. However, the advent and use of avian radar is showing positive results and safety benefits.

Avian Radar

The first dedicated avian radar system for an aerodrome was deployed in the UK, in the winter of 2002 at RAF Kinloss in order to manage the birdstrike risk from skeins of Canada Geese that were moving across the airfield to feed on farm fields. Today, commercially produced avian radars from various manufacturers such as DeTect in the US, Accipiter in Canada and Robin Radar in Europe are in operational use by the US Air Force and Navy, and at several commercial airports in the US, Europe and Africa. The concept of operations for Avian Radar systems is crucial to utilising them on an airport. The RAF Kinloss experience provides a good example of how bird activity data can be successfully integrated into flight operational considerations. This same concept was also successfully used by NASA for 21 launches of the Space Shuttle between July 2006 and July 2011 to ensure that the accent trajectory was clear of birds. The birdstrike concern was brought to the forefront of launch safety following a vulture strike to a shuttle during a launch in July 2005.

Avian radar provides information on the activity of large birds or large flocks of birds hazardous to flight operations that can be acted upon in real time, if the concept of operations is modified to use procedures similar to those utilised for missed approaches, runway incursions by vehicles or personnel or severe weather, windshear and even volcanic ash. The establishment of long term trends and spatial distribution of bird activity around airfields allows identification, documentation and management of birdstrike hazards that evolve and change over time as a result of the dynamic and changing nature of bird populations, migratory patterns, agriculture, land use, seasonal, and climatic conditions. It is difficult to manage this critical risk without data on the timing and level of the risk which only radar provides. Avian radar systems could be considered as the cornerstone tool in modern birdstrike risk assessment and risk management. The UK CAA is currently engaged with the major avian radar providers and seeks to learn from the outcomes of operational trials and currently taking place at places such as Amsterdam Schiphol.

Grass & Habitat Management

However, avian radar is not the only answer. The CAA believes that perhaps the single most important non-technological innovation that an airport can develop in order to manage and minimise bird and wildlife activity within the airport’s boundary – is its airfield grass and habitat.

Effective habitat management has been proven to reduce the number of hazardous birds and wildlife present within the airport boundary. Management techniques, such as a ‘Long Grass Policy’ (LGP) as described in the CAA document Birdstrike Risk Management for Aerodromes, point to the removal or reduction of habitats that attract birds that give rise to the greatest (strike) risk. The key objective of habitat management is to proactively and systematically prevent hazardous birds from being attracted to the airfield environment in the first place, and thereby reduce the reliance on reactive control methods to prevent strikes. Trials and studies at airports have proved a direct correlation between an effective LGP and a reduction in birdstrikes by certain bird species, concluding that good quality airfield grass, free from weed and moss infestation, grown to the desired optimum height, will act as an effective first line of defence in keeping birds away from airfields. The CAA encourages and supports new research into this area and is currently engaged with a number of organisations carrying out trials of ‘bird deterrent grasses’.

The Future

So what could or should the aviation industry do about birds? Should manufacturers be building newer, stronger, more robust aircraft engines? Modern aircraft engines today are designed and built to be resistant to multiple birdstrikes from birds of up to 4.5lb (2kg) in weight, but we know from bird census data that large birds and water fowl populations are increasing and that these birds are getting bigger and heavier, so is there now an imbalance in the design specifications? Paradoxically, new generation higher-bypass engine inlets, or ‘bird scoops’ as they are sometimes referred, are approximately 27% larger than the current aero engines, thus increasing the intake area exposed to birds. In North America, it is estimated that there are now over 36 species of bird which weigh more than 4lb. These populations have increased for the last 30 years and most of these birds exist in flocks, sometimes large flocks. History teaches us that large flocking birds are a significant safety hazard to aircraft. The CAA highlighted this specific flight safety threat to industry as far back as 2002, but has anything really changed since then?

In the future, industry must find new ways to separate aircraft from birds. The US Department of Transport Inspector General recently said in reviewing the FAA’s approach to its regulatory oversight concerning airports and birdstrikes, that, “…the current path is ineffective. We need new thinking, new partnerships, new solutions and we need new leadership”.

World Birdstrike Association

Perhaps the new World Birdstrike Association (WBA) which evolved from the International Birdstrike Committee (IBSC) in June 2012, can be the catalyst, as the global voice in bringing together under one international umbrella rule makers, regulators, airports, airlines, engine and airframe manufacturers and conservation stakeholders from around the world to address the birdstrike issue. The WBA has recently announced that a meeting shall take place in the Netherlands, in April 2013, in order to establish a joint global steering committee for the reduction of birdstrike risk to aviation, reporting to the governing bodies that have committed to attend, represented and participate. Further details may be found on the WBA website at or via email to

Birdstrike Committee

In accordance with ICAO recommendations, the UK CAA hosts an annual national Birdstrike Committee (BSC). The purpose of the BSC is to engage aviation stakeholders, government organisations and other agencies, to serve as a focal point dealing with birdstrike related issues – primarily, an information exchange, to share information and best practice and also to act as an informal consultative group for the regulator when considering new strategies and policies.

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