Christchurch Airport had 304 reported bird strikes last year, the highest in the country. Photo / George Heard
By Keiller MacDuff of RNZ
The Civil Aviation Authority (CAA) is yet to decide if it will investigate the bird strike that resulted in an emergency callout at Christchurch Airport for a Fiji Airways flight.
The Boeing 737-808 was forced to circle for two hours to burn off fuel to meet the required landing weight after it was struck shortly after take-off by what is thought to have been a substantial flock of birds on Thursday afternoon.
The plane destined for Nadi had more than 170 passengers on board and landed back in Christchurch with a dent in its nose and a smear of blood on an engine.
A CAA spokesperson said bird strikes did not normally require further investigation, but it would wait until the airline formally filed its report for review.
Shaken passengers said they felt the impact and were dizzy from going in circles but were unfazed about boarding another plane to reach their destination on Friday.
Bird strikes are relatively uncommon in New Zealand, with an average of around 1500 reported strikes per year, or four strikes for every 10,000 aircraft movements.
Christchurch Airport had 54 reported bird strikes last year, the highest in the country, followed by Napier with 45. CAA figures record both strikes and near strikes as “bird incidents”, and reported 304 in Christchurch and 237 in Napier in 2024.
Once the size of the airport was factored in, Christchurch slipped down the league table.
In 2024, Napier had the most bird incidents per 10,000 flights (102), followed by Invercargill (43), Hamilton (43), Rotorua (40), and Tauranga (36). Christchurch was sixth out of thirty airports and aerodromes, with 31 strikes and near strikes per 10,000 flights.
In the first half of this year, there were 103 reported bird strikes and near strikes at Christchurch Airport - 20 per 10,000 flights - compared to 17 per 10,000 flights at Wellington Airport and six at Auckland Airport.
Avian ecologist Tirth Vaishnav said bird strike was likely significantly under-reported in the aviation industry because there might be little to no damage, pilots might not register the impact and carcasses on the runway were sometimes the first ground staff learnt of a collision.
Research showed there were also discrepancies in how information was recorded and reported between countries and airports, which should be improved, he said.
“The data collection and communication was really varied. There was no standardisation,” he said.
An Australian Transport Safety Bureau paper estimated about 15% of strikes were reported in the United States, 30% in Canada and fewer than 50% in Australia, while other estimates put the reporting rate at 20% globally.
Some airports were reluctant to report strikes because they considered it a reflection on their performance, but Vaishnav said that was not the case and improved standardisation and transparency would make data more accessible and assist in analysing the problem on a global scale.
Researchers found bird strikes were more common during late autumn in both hemispheres, which was likely because of fledgling season with more birds in the air.
Vaishnav said larger migratory species tended to do more damage but large flocks of smaller birds also posed serious risks and it mattered where the bird struck the plane, with engine and windscreen strikes potentially more of a risk.
Climate change was shifting birds’ migratory and breeding patterns and could have implications for bird strike frequency, he said.
According to a CAA report, doubling the size of the bird in a collision doubled the energy of the impact, but doubling the speed of the aeroplane meant the energy of the impact was quadrupled.
Even a light aircraft travelling at 90 knots that collided with a small half-kilogram bird could cause enough damage to badly dent or tear open aircraft surfaces, shatter windscreens, rupture hydraulic lines, damage oil coolers and air intakes and smash landing lights.
While one bird could result in significant structural damage, flocks of birds created the worst hazard, the CAA said.
“Starlings weigh only about 85g each but a flock of them has been responsible for at least one serious aircraft accident,” the report said.
“Some waders will rest and feed only a few metres away from taxiing or departing aircraft. If it becomes necessary to move to avoid being run down, the birds may fly off a few metres and continue feeding but if startled by an unusual movement or noise they may take to the air in panic and fly into the path of the aircraft.
“Some birds will occasionally try to outfly an aircraft, turning out of its flight path only at the last second. A hawk may even attack an aircraft, viewing it as potential prey when seen from a great distance and discovering its error too late.”
– RNZ