The hazards of bird strikes

On December 29, 2024, a Boeing 737-800 aircraft on a flight from Thailand to South Korea crash-landed at Muan International Airport, South Korea, killing 179 of the 181 people on board.

The flight was operated by Jeju Air Co Ltd, the largest South Korean low-cost airline.

The accident marked the deadliest aviation disaster involving a South Korean airliner since the 1997 crash of Korean Air Flight 801 in Guam and became the deadliest aviation incident on South Korean soil. This was also the first fatal crash in the history of Jeju Air, which was 19 years in existence at the time of the accident.

Accident investigators are gathering evidence to determine the cause of this accident. However, preliminary data seems to suggest a landing gear hydraulic system failure linked to a bird strike.

A bird strike is a collision between an airborne animal, usually a bird or bat, and a moving aircraft.

The term is also used for bird deaths resulting from collisions with structures, such as power lines, towers and wind turbines.

Bird strikes are a significant threat to flight safety causing a number of aircraft accidents, some with human casualties.

There are approximately 13,000 bird strikes annually in the US alone.

However, the number of major accidents involving civil aircraft is quite low. The majority of bird strikes cause little damage to the aircraft, but the collision is usually fatal to the birds involved.

Vultures and geese are the most hazardous types of birds to aircraft in the US.

Most accidents occur when a bird or group of birds collide with the windscreen or are sucked into the engine of a jet aircraft.

These cause damages that have been estimated at US$400 million annually within the US and up to US$1.2 billion to commercial aircraft worldwide.

Bird strikes happen most often during takeoff and landing, or during low-altitude flight. However, bird strikes have also been reported as high as 20,000 to 30,000 ft above the ground.

Bar-headed geese have been seen flying as high as 33,383 ft above sea level.

An aircraft over the Ivory Coast collided with a Rüppell's vulture at the altitude of 37,100 ft, the current avian height record.

The majority of bird collisions occur near airports during takeoff and landing. The point of impact is usually any forward-facing edge of the aircraft such as a wing leading edge, nose cone, jet engine cowling and engine inlet.

Jet engine bird ingestion is extremely serious due to the rotation speed of the engine fan and engine design. As the bird strikes a fan blade, that blade can be displaced into another rearward blade, causing a cascading failure.

Jet engines are particularly vulnerable during the takeoff phase when the engine is turning at a very high speed and the aircraft is at a low altitude where birds are more commonly found.

The impact force of a bird strike on an aircraft depends on the weight of the bird and the speed of the aircraft at the point of impact.

The first recorded bird strike fatality was reported in 1912 when aero-pioneer Calbraith Rodgers collided with a gull which became jammed in his aircraft control cables.

He crashed into the ocean off Long Beach, California and drowned.

The greatest loss of life directly linked to a bird strike was on October 4, 1960, when an Eastern Air Lines Lockheed L-188 Electra, flying from Boston to Atlanta flew through a flock of common starlings during take-off, damaging all four engines. The aircraft crashed into Boston Harbor shortly after takeoff, with 62 fatalities out of 72 passengers.

NASA astronaut Theodore Freeman was killed in 1964 when a goose shattered the plexiglass cockpit canopy of his Northrop T-38 Talon.

Shards of plexiglass were ingested by the engines, leading to a fatal crash.

The most notable bird strike occurred on January 15, 2009, when a US Airways Airbus A320-214 aircraft powered by two CFM International CFM56-5B4/P turbofan engines struck a flock of Canadian geese during climb-out from New York City's LaGuardia Airport, at an altitude of 2,818 feet.

The captain, a former US Air Force pilot, realised that both engines had shut down. Attempts at engine restarts were futile. The aircraft slowed but continued to climb for a further 19 seconds, reaching about 3,060 feet at an airspeed of about 185 knots, then began a glide descent, accelerating to 210 knots. The captain radioed a mayday call to New York Terminal Radar Approach Control and together with ATC examined all the available options.

Eventually, the captain determined that the best option was to execute an unpowered ditching in the Hudson River.

All 150 passengers, the three flight attendants and two pilots survived the water ditching.

The NTSB ultimately ruled that the captain had made the correct decision to ditch the aircraft in the Hudson River.

There are occasional bird strikes at TT’s two international airports. Birds tend to nest in the environs of the Piarco International Airport due to a high natural water table in the area. Piarco is an indigenous word for water.

Several years ago, the runway at the ANR Robinson Airport was extended to 9,000 feet to accommodate large jet aircraft. This extension required the reclamation of land eastwards which created a lagoon north of the runway end. This lagoon is a feeding ground for birds.

The Airports Authority of TT (AATT) is required to have an Aerodrome Manual approved by the TT Civil Aviation Authority (TTCAA) for both the Piarco and ANR Robinson International Airports.

The TTCAA regulations require the AATT-approved aerodrome manuals to contain particulars of the procedures to deal with the danger posed to aircraft operations by the presence of birds or mammals in the aerodrome flight pattern or movement area.

The procedures must include the arrangements for assessing wildlife hazards, implementing wildlife control programmes and the names and roles of people responsible for dealing with wildlife hazards and their telephone numbers during and after working hours.

The TTCAA is responsible for ensuring compliance by the AATT with the approved aerodrome manuals procedures.