South Korea plane crash: Bird strike to blame or more factors at play?

By Rabia Ali

ISTANBUL (AA) - Following South Korea's deadly plane crash on Sunday which led to the death of 179 passengers and crew, the focus is now on investigations into the deadly accident, with various theories -- from bird strikes to other complicating factors -- being evaluated by analysts around the globe.

Reports suggest that the South Korean authorities investigating the deadly Boeing 737-800 plane crash at Muan International Airport are pursuing the possibility of a bird strike that led to the crash.

A Jeju Air pilot reportedly told the air traffic control that the passenger plane "suffered a bird strike before it crashed."

Experts, however, believe that a bird strike alone cannot be the sole cause of the deadly accident.

"The Jeju Air crash likely resulted from a combination of technical, operational, and environmental factors extending beyond the reported bird strike. One key focus will be system failures," Marco Chan, a senior lecturer in aviation operations at Buckinghamshire New University told Anadolu.

According to Chan, the bird strike appears to have been a "contributing factor," and the crash which is one of the worst disasters in the country's aviation history, likely involved "multiple interrelated issues."

- How deadly are bird strikes?

Highlighting the frequency of bird strikes in aviation, Chan, a former pilot, said that over 13,000 are reported annually worldwide, according to the International Civil Aviation Organization (ICAO).

However, compared to the approximately 40 million commercial flights operated globally each year, a pre-pandemic figure from the International Air Transport Association (IATA), a bird strike occurs in roughly one out of every 3,000 flights, he added.

"Most bird strikes cause no significant damage, as modern aircraft are built to withstand such events. However, certain factors can increase the risk," says Chan.

"Larger birds or collisions with multiple birds are more likely to cause damage, especially if they strike engines, windshields, or critical systems like control surfaces or hydraulics."

Elaborating further, Chan said that aircraft speed amplifies the energy of the impact, and bird strikes often occur during takeoff or landing, when response time is limited.

Severe cases, such as engine failure or loss of system functionality, can test the limits of an aircraft’s design and a crew’s decision-making under pressure, he added.

While rare, there have been catastrophic incidents involving bird strikes, he said.

"US Airways Flight 1549 in 2009 suffered a dual-engine failure after ingesting a flock of geese, resulting in a safe emergency landing on the Hudson River with no fatalities."

"Conversely, in 1960, an Eastern Air Lines Lockheed Electra crashed due to a bird strike, leading to fatalities. These examples show that while bird strikes seldom lead to crashes, under certain conditions, they can escalate into severe emergencies."

- Can a bird strike damage landing gear?

While reports suggest that the malfunction of the landing gear in the Jeju plane is being linked to the bird strike, Chan believes that it is less common for a bird strike to directly damage the landing gear.

This is due to its position and design, which is typically more shielded than engines or windshields, he explained.

"However, bird strikes can indirectly cause landing gear malfunctions if they damage hydraulic lines, control systems, or related components."

Citing example, Chan said that if a bird is ingested into an engine, it can cause significant damage, potentially leading to engine failure. This can result in hydraulic pressure loss if the affected engine powers the hydraulic system, preventing the landing gear from deploying properly.

According to Chan, the modern aircraft like the Boeing 737-800 have backup systems for such scenarios, including the Landing Gear Alternate Extension procedure outlined in the Quick Reference Handbook (QRH).

"This allows pilots to manually deploy the landing gear using gravity in the event of hydraulic failure. However, this may not work if the bird strike caused direct damage to the landing gear mechanism or critical hydraulic components."

- Investigation

The expert also pointed out how the investigators will closely examine whether the bird strike directly or indirectly affected systems connected to the landing gear, including hydraulic lines and mechanical components, and whether engine ingestion played a role in cascading failures that led to the malfunction.

"Investigators will determine if the bird strike caused cascading issues, such as hydraulic failures, that affected the deployment of landing gear, slats, or flaps—critical systems for deceleration and stability during landing," Chan said.

He also pointed out how the timeline of events in South Korea's deadly crash was another crucial aspect, with investigators to access whether more time for troubleshooting and preparation could have changed the outcome.

"A bird strike warning was issued at 08:57 local time, followed by the crew’s Mayday declaration at 08:58. The crash occurred five minutes later, at 09:03. This compressed timeline suggests the aircraft was in a critical condition, requiring a rushed landing."

Experts are also questioning the presence of the concrete wall, highlighting how runway and approach factors are also crucial in the investigations.

"Runway 19, where the crash occurred, has a -0.2% downhill slope, which increases the landing distance required. Combined with potential system failures, this may have contributed to the runway overrun."

"The concrete fence 300 meters beyond the runway end will be reviewed, as such barriers should ideally be frangible—designed to break on impact—to minimize damage during overruns."

Highlighting that although weather conditions were reportedly calm and clear according to the METAR (Meteorological Aerodrome Report), Chan said that this will still be examined to rule out unexpected environmental influences.