A bird strike is a collision between an aircraft and one or more birds, occurring during flight or on the ground during takeoff or landing. These incidents are a known aviation hazard, occurring frequently worldwide, with over 17,000 wildlife strikes reported annually in the US alone. While most bird strikes cause minimal damage, certain events can lead to severe outcomes, as exemplified by the “Miracle on the Hudson” incident. The aviation industry employs various strategies to manage this risk.
How Aircraft Are Affected
Aircraft engines are particularly susceptible to damage from bird strikes. When a bird is ingested into a jet engine, the impact can damage rapidly rotating fan blades, compressors, or turbines, potentially leading to a reduction in thrust or a complete engine shutdown. Engines are engineered to endure the ingestion of birds up to a certain weight without catastrophic failure, but larger birds or flocks can cause significant operational issues. For instance, a 5 kg bird striking an aircraft at 275 km/h generates substantial kinetic energy.
Aircraft windshields are another common impact point. A bird strike can cause the windshield to crack or shatter, severely limiting a pilot’s forward visibility. Aircraft windshields are multi-layered and designed for bird strike resistance, but extreme impacts can result in penetration, risking injury to the flight crew or introducing debris into the cockpit. The leading edges of wings, tail surfaces, and the main fuselage can also sustain damage, such as dents, punctures, or compromised structural integrity.
During takeoff or landing, bird strikes can affect landing gear components. While direct damage to the landing gear is less common, impacts can disrupt hydraulic lines or control systems. The extent of damage from any bird strike depends on several factors, including the bird’s size, the aircraft’s speed, and the precise location of the impact on the airframe.
Pilot and Air Traffic Control Actions
When a bird strike occurs, pilots are trained to prioritize maintaining control of the aircraft. Their immediate focus is to assess any potential damage by monitoring engine instruments and performing visual checks. This initial assessment guides their subsequent actions, ensuring continued safe flight. Pilots will then activate relevant non-normal or emergency checklists for any system malfunctions.
Following this assessment, pilots promptly communicate with air traffic control (ATC) to report the incident. They provide details about the impact, any observed damage, and their intentions, such as continuing to their destination, diverting to an alternative airport, or returning to the origin. This communication allows ATC to prepare for the aircraft’s arrival and manage other air traffic.
In situations where damage is substantial or safety is compromised, pilots may declare an emergency, such as a “Pan-Pan” or “Mayday.” This signals the severity of the situation to ATC, granting the aircraft priority for landing and ensuring ground services are ready upon arrival. The decision to divert or return to an airport is based on the nature and extent of the damage, aiming to land at the nearest suitable airfield for inspection and necessary repairs. ATC supports the affected flight by separating it from other traffic and providing essential information.
Post-Strike Procedures
After an aircraft lands safely following a bird strike, it undergoes a thorough inspection by maintenance crews. This involves a detailed visual examination of all potential impact areas, with particular attention given to engines, wings, and the fuselage. Maintenance personnel meticulously clean any bird remains and then re-inspect the cleaned areas to uncover any hidden damage.
Once the inspection is complete, any damage found is carefully classified. This classification ranges from minor cosmetic issues to more significant structural damage or damage requiring engine repair or replacement. Repairs are then carried out in strict adherence to aviation maintenance regulations and safety standards. This might involve patching small dents, replacing damaged engine fan blades, or in more severe cases, installing an entirely new engine.
An aircraft cannot return to service until all necessary repairs are completed and certified by qualified engineers. This rigorous certification process ensures the aircraft meets all airworthiness standards before resuming operations. All bird strike incidents are reported to aviation authorities, such as the Federal Aviation Administration (FAA) in the United States and the International Civil Aviation Organization (ICAO) globally. This data collection is crucial for analyzing patterns, identifying high-risk areas, and informing future safety improvements in aircraft design and operational procedures.
Minimizing Bird Strike Risks
Airports implement comprehensive wildlife management programs to reduce the incidence and severity of bird strikes. These programs include habitat modification, such as removing attractive vegetation or managing water sources on and around the airfield to deter birds. Hazing techniques, using pyrotechnics, distress calls, or lasers, are also employed to scare birds away, and in some cases, trapping and relocation may be utilized.
Aircraft design incorporates features aimed at enhancing bird strike resistance. Modern aircraft are constructed with reinforced windshields that can withstand significant impacts and engine casings designed to contain potential damage from bird ingestion. Engines undergo rigorous testing to ensure they can safely shut down or continue operating at reduced thrust after ingesting a bird of a specified weight.
Pilots receive specific training focused on bird strike avoidance techniques. This training includes adjusting flight altitudes when possible, particularly during takeoff and landing phases where bird activity is higher, and using landing lights to increase aircraft visibility to birds. Pilots are also thoroughly trained in the emergency procedures to follow should a bird strike occur.
Advancements in technology also contribute to risk reduction. Some airports utilize bird radar systems that detect and track bird activity in real-time, providing alerts to both pilots and ground teams about potential bird hazards. This information allows for proactive measures, helping to predict and mitigate threats.