The Boeing 737-800, which crashed in South Korea, is among the world's most widely used aircraft models.

• In South Korea's worst air disaster in decades, 179 people were killed when Jeju Air Flight 7C2216 crash landed at Muan International Airport, leaving only one survivor.
• The cause of the fatal belly-landing of a Boeing 737-800 is being investigated by investigators.
• Nearly 4,400 aircraft of this model are in service worldwide, as stated by Cirium.

Investigators are working to determine the cause of a Jeju Air flight that crashed at Muan International Airport in southwestern South Korea, killing all but two of the 181 passengers and causing the nation's worst air disaster in decades.

An emergency inspection of South Korea's 737-800s, the type of plane used on the fatal Jeju Air Flight 7C2216, was ordered by the acting president, Choi Sang-mok.

The Boeing 737-800 is a widely used airplane with a solid safety record, despite being older than the Boeing 737 Max, which was involved in two fatal crashes in 2018 and 2019, killing all 346 people on board. The 737 Max was grounded for nearly two years, and a flight-control system, which was later adjusted, was found to be responsible for both accidents.

Approximately 17% of the world's in-service commercial passenger jet fleet consists of nearly 4,400 older Boeing 737-800s, according to aviation-data firm Cirium.

According to Cirium, the average age of the world's 737-800 fleet is 13 years old, and the last of the series of planes were delivered five years ago.

The plane that was involved in the crash in 2017, which was previously operated by European discount carrier Ryanair, was delivered to Jeju Air. The plane was about 15 years old.

It is unlikely that investigators will discover a design flaw in the long-enduring aircraft, according to aerospace experts.

Richard Aboulafia, managing director at AeroDynamic Advisory, an aerospace consulting firm, stated that it is almost impossible to believe that they will discover a design flaw at this stage.

The unusual incident has raised more questions than answers, such as why the landing gear wasn't deployed, even though Boeing 737-800 pilots can drop the landing gear manually in the event of a hydraulic malfunction.

One theory suggests that a bird strike may have caused the engines to malfunction.

According to Jeff Guzzetti, a retired air safety investigator with the U.S. National Transportation Safety Board and the Federal Aviation Administration, if the altitude they were at caused them to not have enough time to do emergency checklists, it could have been a contributing factor to the accident. Additionally, if the plane hadn't hit a pile of dirt and a hard wall at the end of the runway, the accident could have been more survivable. The area in question contained a localizer that assists in guiding aircraft.

The NTSB is heading the U.S. investigation team, which also includes the FAA, as the aircraft was constructed and approved in the United States.

The country where the accident occurred will lead the investigation under international protocols.

On Monday, Boeing shares dropped over 4% early on, but later recovered to end the day with a 2.3% decline, following local officials' call for inspections on 737-800s operated by South Korean airlines.