Boeing 737-800 is among world’s most common aircraft

Accident investigators are trying to figure out what caused a Jeju Air flight to land belly-up without its landing gear lowered at Muan International Airport in southwestern South Korea, killing all two of the 181 people on board as it burst into flames in the nation’s worst air disaster in decades.

South Korea’s interim president, Choi Sang-mok, ordered a state of emergency inspection of the country Boeing 737-800, the type of aircraft used in the fatal Jeju Air Flight 7C2216.

The Boeing 737-800 is one of the most used aircraft in the world, and has a strong safety record. Predate the Boeing 737 Max, the type that was involved two fatal crashes in 2018 and 2019 that killed all 346 people on board those flights. The 737 Max was in the ground for almost two yearsand a flight control system, which was later tweaked, was involved in both crashes.

There are nearly 4,400 of the older Boeing 737-800s in operation worldwide, according to aviation data company Cirium. This means that the model makes up about 17% of the commercial passenger jet fleet in service in the world.

The average age of the global 737-800 fleet is 13 years, according to Cirium, and the last of the series of aircraft were delivered about five years ago.

Jeju Air took delivery of the plane that was involved in this weekend’s crash in 2017. It was previously operated by European discount carrier Ryanair, according to Flightradar24. The plane involved in the crash was about 15 years old.

Aerospace experts say it’s unlikely investigators will find a design problem with the long-haul plane.

“The idea that they would find a design flaw at this point is borderline inconceivable,” said Richard Aboulafia, chief executive of AeroDynamic Advisory, an aerospace consulting firm.

A full investigation could take more than a year, and the unusual incident has raised more questions than answers, such as why the landing gear was not deployed. Even with a hydraulic malfunction, Boeing 737-800 pilots can lower the landing gear manually.

One theory involves a possible bird strike that disabled the engines.

“If it happened at the altitude they were at, they wouldn’t have had time to do emergency checklists,” said Jeff Guzzetti, a retired aviation safety investigator with the U.S. National Transportation Safety Board. United States and the Federal Aviation Administration. He also said that if the plane had not hit a hard wall at the end of the runway, the accident could have been more survivable.

The NTSB is leading the U.S. team of investigators that also includes Boeing and the FAA, since the aircraft was manufactured and certified in the United States.

Under international protocols, the country where the accident occurred will lead the general investigation.