Although the total number of bird strikes1 reported in Australia increased between 2012 and 2013 (Figure 1), the bird strike rate in recent years has decreased slightly (Table 1), the Australian Transport Safety Bureau (ATSB) says.
Reported bird strikes numbered 1,769 in 2013, up from 1,644 in 2012, the ATSB said in its report, Australian Aviation Wildlife Strike Statistics, 2004–2013, released in December 2014. Over the 10-year period from 2004 through 2013, the agency received reports of 14,571 bird strikes, most of them involving high-capacity air transport aircraft. The number of strikes reported annually increased over the 10-year period from 1,085 in 2004 to 1,769 in 2013.
The number of reported animal strikes during the 10-year period was considerably lower, averaging 36.8 strikes per year and ranging from a low of 31 strikes in 2005 to a high of 48 in 2010. In 2013, the number totaled 42. In eight of the 10 years, high-capacity aircraft were involved more often than aircraft in four other categories: low-capacity, general aviation, military and unknown.
“Occurrences involving aircraft striking wildlife, particularly birds, are the most common aviation occurrence reported to the Australian Transport Safety Bureau,” the agency said. “Birds and other animals are hazards to aviation that will always be present and so need to be managed, both in terms of reducing the likelihood of a wildlife strike and reducing the consequences of strikes that occur.”
Since 2011, the bird strike rates have decreased at seven of the country’s major airports, including those in Adelaide, Melbourne, Perth and Sydney; the greatest increase was reported in Darwin, where the strike rate more than doubled between 2011 and 2013, the report said.
Data were incomplete for the total rate of bird strikes per 10,000 aircraft movements in 2013, but the rate for high-capacity air transport operations was 7.45 per 10,000 movements, up slightly from the rate of 7.3 strikes per 10,000 movements reported in 2012 but down from the 10-year high of 8.38 per 10,000 movements reported in 2011.
When the ATSB report was released, data were not available for charter operations (a part of the low-capacity category) or for general aviation. Bird strikes in those two categories, however, have consistently been well below the high-capacity aircraft rate.
“It is likely that the speed and size of these aircraft, longer takeoff and landing rolls, and large turbofan engines are factors contributing to the higher rate,” the report said.
For airplanes, most reported bird strikes occurred during the takeoff (38 percent) or landing (36 percent) phases of flight, the report said (Figure 2). The distribution pattern differed for helicopters, with strikes most often reported during cruise, standing, approach and maneuvering/air work.
“While the high proportion of helicopter bird strikes on the ground (standing) is likely to be due to birds colliding with the moving rotor blades of a stationary helicopter, the lower proportion of strikes during landing and takeoff may be due to the louder and varying noise caused by helicopter rotor speed and pitch changes during these flight phases,” the report said.
Throughout Australia, bird strikes were most common between 0730 and 1030 local time, with a lull between 1330 and 1430 and an increase between 1800 and 2000, followed by a steady reduction until the 24-hour low point in the early morning (Figure 3).
Data showed that about 80 percent of strikes in which a bird was ingested into an engine involved high-capacity air transport airplanes, most of which have turbofan engines.
Data also showed that general aviation had a higher proportion of damaging bird strikes than any other sector, with about 25 percent of general aviation bird strikes from 2004 through 2013 resulting in damage.
Across all sectors, the most commonly damaged aircraft components during the 10-year period were airplane wings and helicopter rotor blades, the report said.
Birds most commonly struck by aircraft in 2012 and 2013 were kites, bats/flying foxes, lapwings/plovers and galahs. The animals most often struck were hares/rabbits, kangaroos, dogs/foxes and wallabies, the report said.
The report noted that bird strikes have not presented significant safety risks to Australian civil aircraft, with no civilian aviation fatalities attributed to bird strikes in reports as far back as 1969. Nearly all (98.7 percent) bird strikes from 2004 through 2013 were classified as low-risk occurrences.