• A Jeju Air plane crashed in South Korea, killing 179 of 181 on board.
• Investigators are considering the role of a bird strike in the crash.
• Bird strikes have not caused many plane losses, and experts say it may not be the only factor.

Bird strike is being considered as a possible cause of the plane crash in South Korea, which killed almost everyone on board.

Although colliding with birds has always been a risk of flying, it has brought down comparatively few modern aircraft.

Some experts said of the Sunday crash that a bird strike was unlikely to be the sole cause.

"A bird strike should be a survivable event," said Sonya Brown, an aerospace-design lecturer at the University of New South Wales, in an interview with The Guardian.

She said that planes are designed to cope with bird strikes. Engine-builders have long tested their designs by launching bird carcasses into running engines to ensure they keep working, as reported by this CNBC article from 2017.

A June report by the US Federal Aviation Administration said wildlife strikes on civilian and military aircraft have killed 491 people and destroyed some 350 aircraft globally between 1988 and 2023.

It said that in the US, 49 civil aircraft were lost because of birds in the period between 1990 and 2023.

Civil aircraft include both airliners and general aviation planes. The latter are more susceptible to damage because many are smaller, have less robust airframes, and single engines.

While that may sound a lot, it represents a tiny fraction of total losses over that period of more than 30 years.

There were more than 27,000 aircraft fatalities between 1988 and 2021, according to the Aviation Safety Network, putting bird strikes as a factor in fewer than 1.8% of deaths. Most of the deaths involve general aviation planes.

Bird strikes on passenger jetliners very rarely bring down an aircraft. The last time it happened in the US was the 2009 crash-landing of the "Miracle on the Hudson", where everyone survived.

Most of the time, bird strikes will cause damage to airlines, but pilots are safely able to land the plane. American Airlines, for example, suffered a bird strike over New York in December and circled back to the airport for an emergency landing, with no reported injuries.

The Jeju crash reason is still unknown

Investigators have yet to give a reason for the loss of the Jeju Air flight, a Boeing 737-800.

An official in South Korea's transport ministry official said the airport's control tower issued a bird strike warning before the crash, Reuters reported.

The fire chief at Muan International Airport, where the plane crashed, said in a televised briefing that an investigation will consider whether birds stuck the plane.

South Korea's acting president ordered an emergency inspection of the country's airline operations. And the government said it will audit all 101 of the country's 737-800s with US investigators.

But a bird strike is being considered as a cause, or a possible factor. And other issues have been reported, too.

Video footage showed that the plane landed without its landing gear deployed.

Keith Tonkin, the managing director of Aviation Projects, an aviation consulting company in Australia, previously told BI: "It appears that the aircraft wasn't configured for a normal landing — the landing gear wasn't down, and it looks like the wing flaps weren't extended either."

Commentators have also pointed to the design of the airport — the plane came to a hard stop when it hit a solid wall near the runway.

Jeff Guzzetti, a former accident investigator at the US's Federal Aviation Administration and National Transportation Safety Board, told The New York Times that plane crashes are typically the result of multiple factors at once.

This is known as the "Swiss Cheese Model" in aviation, a theory that says a string of multiple smaller errors often lead to an air accident.

"The aviation industry is built on redundancy, and there are very few single-point failures in airplane design or airplane operations," he said. "Typically, it's a combination of factors."

• American Airlines briefly grounded all its US flights over a technical issue on Tuesday morning.
• The airline told BI that a "vendor technology issue" had affected its flights.
• Certain cancellations and delays trigger compensation under new federal rules.

American Airlines grounded all of its flights across the US for about an hour on Tuesday, saying it was experiencing technical issues.

Later Tuesday morning, American flights were back in the air. It was unclear whether the delays would reverberate through its network and cause additional issues on a big travel day ahead of Christmas.

Data from aviation analytics company Cirium and shared with Business Insider showed that only around 37% of American's flights are running on time as of 2 p.m. Eastern Time. Still, less than 1% have been canceled.

"Based on previous such incidents, it appears American has been able to maintain its schedule, albeit with delays," Cirium said in a statement.

Cancelations could grow, Cirium said, if crews "time out" — or run out of time they're allowed to fly by regulations.

Under new Department of Transportation guidelines, some passengers could be entitled to compensation if their flights are delayed or canceled.

The Federal Aviation Administration said in an advisory statement early on Tuesday that the airline's flights across the US were grounded. An update about an hour later said the nationwide ground stop was canceled.

American Airlines told BI in a statement that a "vendor technology issue briefly affected flights." That issue has been resolved, and flights have resumed.

"We sincerely apologize to our customers for the inconvenience this morning," American said. "It's all hands on deck as our team is working diligently to get customers where they need to go as quickly as possible."

The airline said the technology issue affected the systems needed to release flights, and the ground stop lasted about an hour.

Bloomberg described online posts as saying the issue prevented the airline from calculating weight and balance requirements for its flights.

More than 2,400 flight delays on Christmas Eve

The Cirium data shows that 63% of American's 3,900 global scheduled flights were delayed after Tuesday's ground stop. Planes were getting back in the air by mid-morning Eastern Time, with only 19 total cancellations.

Most of American's flights are running within two hours of their originally scheduled departure time, per Cirium, though some are reaching three hours or more.

FlightAware data shows American's hubs in Charlotte, North Carolina, and Dallas/Fort Worth are the most affected airports, with about 400 and 500 flight delays, respectively, as of 2:00 p.m. ET.

A weather advisory in effect in the Dallas area was further disrupting flights.

Federal rules about customer compensation

Users on X said they were made to get off their planes on Tuesday morning.

New Department of Transportation rules say customers are entitled to automatic refunds for flights that are canceled or "significantly changed," including domestic flights that arrive at least three hours later than scheduled. To receive a refund, a customer must not accept a changed booking.

Most airlines, including American, offer meal vouchers to travelers who wait three or more hours because of a delayed or canceled flight that was within the airline's control. American's technical issues would fall under that category.

Many provide hotels for an overnight delay or cancellation, as well as transportation to and from the airport. It's unclear whether American's Tuesday disruptions will spill over into Wednesday.

The disruption comes on Christmas Eve, one of the biggest travel days of the year.

The Transportation Security Administration said it expected to screen almost 40 million people through airports over the holidays, an increase of more than 6% from last year.