Bird strikes are a significant threat to flight safety and can lead to human consequence. However, it is estimated that only one fatality occurs due to bird strikes every billion flight hours. Bird strikes usually don’t deal major damage to an aircraft, but the collision is fatal for the birds most of the time.
The majority of accidents caused by bird strikes occur when the bird is either sucked into the engine of a jet or when the bird flies into the windscreen. These accidents are estimated to cost commercial airlines worldwide up to $1.2 billion dollars annually, and $400 million in the US alone.
The Canada goose has been crowned as the third most lethal animal to aircraft behind deer and vultures. There are roughly 240 collisions between aircraft and the Canada goose every year in the US.
How bird strikes damage aircraft
90% of bird strikes occur at or near an airport whilst a plane is landing, taking off, or at a low altitude. However, they have been reported to occur as high as 4,500 m (15,000 feet). Some geese are known to fly as high as 7,290 m (23,000 feet) for short periods during their migration, with the Bar Headed goose using a ‘rollercoaster’ route to make use of thermal currents and jet streams for energy conservation.
The amount of damage the bird does to the aircraft all depends on the size, weight, and speed of the bird and aircraft. The heavier and faster the bird is, the more potential damage there is to the aircraft.
Bird strikes almost always damage the forward-facing areas of the aircraft – the windscreen, nose cone, and engines. Bird strikes to the nose cone can cause dramatic damage, but rarely present a reason for the flight to be aborted. Windscreen damage can be more serious, as a shattered windscreen can mean loss of cabin pressure, and would usually necessitate a diversion to a nearby airport.
The biggest risk to flight safety is when a bird gets caught in the engine of an aircraft. This is known as jet engine ingestion, and can cause the engine to fail. As most airplanes are capable of flying on one engine without issue, this would mean a diversion to the normally nearest airport, but nothing to be too concerned about. However, there are cases where birds have been ingested by both engines – a very rare occurrence – causing a dual engine failure, including one very famous example…
US Airways flight 1549
On January 15, 2009, an Airbus A320 on route to Charlotte from New York City’s LaGuardia Airport flew into a flock of birds shortly after the plane had taken off. Unusually, the bird strikes affected both engines, causing a dual engine failure.
With no power, there was no suitable airport for pilots Chesley Sullenberger and Jeffrey Skiles to use for an emergency landing. Instead, they decided to glide the aircraft into the Hudson River where all 155 people onboard, including 5 crew and 150 passengers, were rescued by boats. Only a handful of people were injured.
This flight has been crowned the ‘Miracle on the Hudson’ and is considered to be the most successful drilling in aviation history. All crew onboard were awarded the Master’s Medal of the Honorable Company of Air Pilots and Air Navigators for their “heroic and unique aviation achievement.” The incident was later made into the 2016 hit film ‘Sully’, which starred Tom Hanks as Sullenberger.