Author: Ting Lei
The event of an airborne animal hitting an airplane in flight is referred as bird strike. Although bird strikes are a lesser hazard to aviation than some other well-known hazards such as air turbulence and icing, it still poses a sizable threat to airline safety and do present risk that needs to be addressed. According to Bird Strike Committee USA, wildlife strikes cause over $650 million annually in damage to U.S. civil and military aviation.
The goal of this article is to discuss some of the characteristics of bird strikes, raise the awareness of this issue, and help reduce the likelihood of bird strikes.
2.1. Software Used
I used Excel to preprocess the dataset and Tableau 10.1 to visualize the data.
The data is acquired from Federal Aviation Administration website. It contains a total of 140,537 bird strike records in United States from the year of 2000 to the end of 2015. The dataset documents each incident of bird strike in terms of date, damage to aircraft, cost to repair, bird species, location, types of Airline, etc., with a total of 94 fields.
According to the U.S. Department of Agriculture, many populations of wildlife species have grown significantly in the last 10 – 20 years and adapted to living in urban environments, including airports. Such explosion in wildlife population has led to the increase in bird strikes as show in the Figure 1 below. The number of strikes reported annually doubled from 6,561 in 2004 to 13,692 in 2014. The number of bird strike records will continue to grow as there is almost a linear increase in the number of incidents in the last decade.
Along with those wildlife that live in the United States, there are also between 500 million to 1 billion birds that migrate over United States each year. And this could explain the fact that although bird strikes happen any time of the year, the prime months for bird strikes falls between July to October, which is the typical migratory season. The figure 2 below depicts the bird strikes in each month, and July to October sum up to 52.2% of the annual total.
Figure 3 describes the number of bird strikes occurred during different phases of flight and time of day, where “phase of flight” is a set of term to categorize the operational phase during the aircraft accident. It is not surprising to see that majority of bird strikes occurring during the day since most flights are in the daytime. However, birds do fly a lot at night which makes the night the second highest time for bird strikes.
Figure 4 describes the height of the aircraft when bird strikes occur. As show in both figure 3 and 4, bird strikes usually occur when an aircraft is flying at low attitudes. Hence, the most common conditions for a bird strike are during approaching, landing, or taking-off with the altitude within 100 feet above ground level. This could be explained by the fact that most bird species fly at a low attitude; however, there is also a great number of bird strikes from 900 feet to 4000 feet above ground level as shown in the Figure 4 below.
While bird strikes most likely to damage the wings and the engines, all areas of an aircraft can be damage as shown in the Table 1 below. A hit in windshield may result in the cracking of the surface of windshield and may possibly disrupt the air pressure inside the cabin. Meanwhile, when wildlife get caught inside the engine, it can possibly cause a disruption in the rotatory motion of the fan blades and result in the failure of the engine.
We must also keep in mind that many bird species are capable of inflicting damage to aircrafts. Between 2000 and 2015, there are over 694 species of birds that were involved in strikes. Although the Mourning Doves are the most found species with 7,025 records in Bird Strikes, with only 2% chance of causing damages, the Mourning Doves had not been listed as the most hazardous bird species to flight (only 135 damaged records). The figure 5 below identified a list of birds that are most hazardous to flight: Gulls (521), Canada goose (496), White-tailed deer (442), Red-tailed hawk (284), Turkey vulture (275). In general, any size of birds is problematic and have the possibility to result in accidents.
Lastly, among the nation’s 30 busiest airports, the five facilities with the top strikes rates from 2000 to 2015 were the Denver Intl. Airport (5,256 strikes), Dallas Intl. Airport (4,150 strikes), Chicago O’Hare Intl. Airport (3,019 strikes), Memphis Intl. Airport (2,680 strikes), as well as the John F Kennedy Intl. Airport (2,653 strikes). However, the top three airports in terms of damaging strikes were Sacramento Intl. Airport (237 damaging incidents), Salt Lake City Intl Airport (170 damaging incidents), and Orlando Intl Airport ( 153 damaging incidents).
In conclusion, bird strikes usually cause no more than minor damage, but they can still pose a threat to flight operations. Pilots and operators should be knowledgeable that bird strikes occur more often in the late summer/autumn season and are more likely to be during the landing phase of the flight when the aircraft is at a low altitude.
Although there had been reported with over 7,000 bird strikes incidents involving Mourning Doves; however, only 135 of the incidents had been reported with damages. Whereas the Gulls lead to the largest number of reported damages with 521 incidents.
Really interesting topic. I like the overall analysis u gave in this case, which helps the reader better understands the problem.
This is a very interesting study and the data was analyzed and presented very well. Another interesting way this data could have been presented would be to associate a dollar amount representative of the damage cost attributed to that certain category. For example, this could help the readers visualize how much total cost each part of the plane is or how much damage done in the day or night costs relative to other times.
Very interesting analysis. Regarding the airports with the most birdstrikes, I’d be interested to know what factors related to the airports and their locales impact the number of bird strikes. Of course, the busier airports naturally have more birdstrikes on account of simply having more flights, but that doesn’t explain why Denver has more than O’hare despite O’hare being a much busier airport. Perhaps O’hare has better controls against bird strikes, which would be an interesting follow-up analysis to dive into.
What an interesting study! I had no idea that bird strikes caused so much damage. It is also interesting how bird populations have grown so much even in urban areas.
I thought your study was well done. One question/comment I have is about how the airports with the most bird strikes did not experience the most damaging bird strikes. Do you have any thoughts as to why that is? Would it be possible to explore a risk adjustment to the data using the types/sizes of birds that live around those different airports? It seems counter-intuitive that the airports with the most strikes would not also experience the most damaging strikes. Thank you for sharing your work!
This was interesting to see the sheer volume of bird strikes experienced at airports! Is the white-tailed deer a species of bird or an actual deer? While I am sure they are hit on the tarmac, I can see how they would cause a lot of damage.
Also Denver, Dallas, & Memphis are cities with a high incidence of bird damage strikes on aircraft. It also seems most strikes occur on approach. It would be interesting to know if the orientation of runways would have something to do with this, as these 3 cities have a number of North – South runways. Chicago & JFK are close to large bodies of water. LA & Atlanta both have large volumes of flights, and both have runways that run mostly West-East. Thanks for sharing.
Thank you for your detailed analysis and visualizations. This information was very clearly conveyed – helping the readers acknowledge this growing problem. I am curious if the Federal Aviation Administration has any information regarding the inter arrival time of the records and whether these incidents occur in groups, as I imagine birds often fly in flocks.
First of all, I had no idea that bird strikes posed such a significant problem for the aviation industry today. I guess that it makes sense when I step back and think about it, but I didn’t think small animals could cause damage to something like an airplane. Second, I’m really interested in understanding why the number of strikes doubled form 2004 to 2014. Are there more planes in the sky, causing the number of birds striking these planes to increase? Or, is it a combination of things occurring causing the linear increase of bird strikes?
Thanks for sharing
Well I did a quick google search and air traffic increased between 2013 and 2014 significantly to 37.4 million flights a year and that is up 2.7% (102,465 flights). Taking the number of bird strikes in 2014 and dividing it by the number of flights in 2014 it gives us 0.0037%. This is the chance that your flight would of been struck by a bird, not necessarily a cause of damage but a bird strike in 2014. The danger is very small, smaller than walking across the street in a major city (assumption).
Number of flights from: https://www.quora.com/How-many-airplanes-fly-each-day-in-the-world
Further digging reveals the following data (obtained from https://www.statista.com/statistics/564769/airline-industry-number-of-flights/):
Total flights (2004) ~ 23.8 million
Total flights (2014) ~ 33 million
So, although there wasn’t a doubling of the number of flights, the increase was certainly substantial (roughly 10 million more flights). Clearly though, this doesn’t explain the doubling of reported bird strikes.
I think there may be two factors at play here. First, the reporting methods may have improved between these two years (e.g. there are better ground radar systems, or new legislation has been enacted to require the reporting of all bird strikes). Second, the increased density of urban areas may cause certain bird species to migrate toward more open spaces, like an airport.
Regardless of the cause, this was an interesting follow up question, Henry.
The report says bird strike causes $650M damages annually but the conclusion says the damages are minor, I believe $650M annual damage is major except your rating is based on loss of life and other factors.
This analysis is interesting. It would be interesting to take this analysis and look at migration paths for Gulls and Mourning Doves. I’m interested to see if the airports fall in the path of migration patterns that is regularly used by the birds. Such analysis could help city planners in future when they plan to build any major infrastructure.
This definitely makes me a little more worried to get on my next flight. I was interested to see how much birds can afflect planes. One question I have is if the airports that experience the most damage are also the areas that the birds with high damage rates originate from
I remember hearing a lot about this problem in 2009 after Sully Sullenberger landed a plane on the Hudson River after the plane struck a flock of geese, causing both engines to fail. I remember hearing some pretty crazy numbers back then about how forceful impacting a goose at the speeds airplanes travel at is. I found this article https://www.telegraph.co.uk/travel/travel-truths/how-dangerous-is-a-bird-strike/ that says that striking a goose in flight causes a force on the plane equivalent to 50,000 pounds. It’s incredible that modern planes are so well engineered that hundreds of these goose strikes happen each year without incident.
I also found information that said after even a minor bird strike, a plane is required to land at the nearest airport. Then passengers must switch planes and a new crew is assigned. I wonder if the cost of this disruption was included in the cost of bird strikes. Regardless, it’s reassuring to see that the problem is more of money than safety, most of the time.
This is a very interesting study. I wonder if the trend for number of bird strikes over time has to do in part with an increase in flights over time? I’m sure aviation travel is growing in addition to the bird population, so it would be interesting to take that into account in the study. It was also really interesting to see that Denver had significantly more bird strikes than other airports. I wonder if this is in part due to Denver’s altitude? I really liked the visuals and I learned a lot about a new topic. Thanks!
Super interesting findings. Bird strikes are more common than I thought. I thought it was very interesting that a lot of bird strikes happen between 1000-2000 feet and am wondering if that is somewhat of an average height when birds are migrating. Something to look into!
Thank you for sharing your analysis. It makes sense that there was more bird strikes during the migratory months compared to regular months. The visual of the most affected airports helped to show where bird strikes happened most often but it would have also been nice to see a geographic map to see if there was any pattern. Another component that I would be interested in analyzing is the type of plane that was affected. Based on material and design of the aircraft, I wonder if there was an effect on the type of damage to the aircraft. Overall, very interesting and useful to ensure the safety of birds migrating as well as customers onboard the plane.
This article made me realize the prevalence of bird strikes in aviation; I had not previously thought that they were as common. The findings here can definitely be useful for assessing the damage of bird strikes over the years. However, it would have been nice to see the article go one step further by offering suggestions of how to apply these findings to help airports save money. If bird strikes are increasing every year, there must be a rising need for solutions to this problem. For example, why do some airports have higher rates of bird strikes? If we knew a reason (e.g. are any of the airports near a heavily forested area?), these airports could potentially think of ways to lower strike rates (e.g. trash collection initiatives around the airfield to protect against scavenging birds being attracted to the area).
This is interesting because of the most famous bird strike in recent history was the landing on the Hudson with Pilot Sully. The lose of the engine was due to a bird strike, I cannot remember the year but was wondering if that one was in the data? Because loosing a whole plane would affected the data in multiple categories.
his is a very interesting study. I wonder if the trend of bird strikes takes into account of increasing flight numbers. Since our aviation is growing. Especially with the fact that budget airlines flies a whole fleet of small airplanes that are more frequent than before, their engines failures tend to be more fatal with bird strikes. Perhaps can zoom into that aspect for further analysis
Interesting, I will definitely be thinking about these finding next time I get on a plane!
Such an interesting topic to analyze! I thought that the factors that you decided to look at like weather and airport were also really interesting to consider. I was just wondering whether the type of aircraft (large ones like Boeing 747 vs small ones like Airbus A318) has an effect on the number of bird strikes.
The analysis is very interesting and it is easy understand the visuals. Thanks a lot for sharing your report.
I am quite surprised none of the airports with the most bird strikes were in the top for number of damaging bird strikes. However, a possible justification could be that the airports with the most bird strikes are in more urban areas and thus have less large birds who inhabit those areas. Also, gulls were found to cause the most damage so it would make sense that coastal airports like Sacramento and Orlando have the most damaging bird strikes.
As someone who has recently become afraid of flying, my nerves were slightly calmed after reading your report and learning that most bird strikes cause no more than minor damage. Another possible reason for Figure 1’s increasing trend rate besides an increase in the number of birds could due to an increase in the number of flights. Figure 8, bird strike by species and the average damage per species, was a noteworthy way to analyze the data and was not something I had considered.
It is interesting to know that Denver international airport was one of the top five airports with highest strike rates.
I found it very surprising that 8% of the bird strikes occur at elevations of 1000 ft!
I think we should always be scared of birds, they can’t be trusted.
I’m shocked to learn the damage a bird can do to an aircraft. I wonder how we can solve this problem in the future.
I really enjoyed reading this report. I found it really interesting that bird strikes tend to increase between the months of July to October (Figure 2). I found it surprising that a large percentage of bird strikes occur over 901 feet because the average bird usually stays under 500 feet during flight.