South Korea plane crash investigation underway, with Jeju Air jet's cockpit voice recorder heading to U.S.
South Korean officials have vowed to find out what caused a Boeing 737-800 passenger jet operated by Jeju Air to crash into flames as it attempted to land over the weekend, killing all but two of the 181 people on board. Days after the crash, there were still far more questions than answers about the country's worst aviation disaster in decades.
Authorities ordered an immediate inspection of all 737-800 aircraft operated by the country's airlines — dozens of planes in total — following the crash, but there was still no clear indication as to whether a system malfunction, human error, or some combination of factors had caused the disaster.
Experts from the U.S. National Transportation Safety Board, the Federal Aviation Administration and Boeing were on the ground inspecting the crash site, and the NTSB was set to play a crucial role in deciphering data from the plane's "black boxes," which record information from the cockpit and aircraft systems.
Officials have warned it could be months before any clear answers emerge. Here is a look at what's known about the Jeju Air crash, and some of the key questions emerging in the wake of the tragedy.
What happened in the South Korean plane crash?
Jeju Air flight 7C 2216 departed from Bangkok, Thailand, and approached for its scheduled landing Sunday at Muan International Airport in southern South Korea.
After an initial failed landing attempt, the Boeing 737-800 received a bird strike warning from the ground control center. It then ascended again before trying to land a second time.
Two minutes later, the plane's crew sent a distress signal and attempted to land on a different runway. The plane touched down three minutes later without lowering its nose landing gear.
It skidded along the runway at high speed, overshot the end of the runway and slammed into a concrete fence, bursting into a fireball. The only survivors were two crew members rescued from the tail section.
Observers say videos of the crash suggested the plane was suffering from suspected engine trouble, but the landing gear malfunction was likely the main reason for the crash.
The plane's flight data and cockpit audio recorders — the so-called "black boxes" — were recovered quickly and first moved to a research center at Seoul's Gimpo International Airport for analysis. On Wednesday, however, the country's deputy minister for civil aviation, Joo Jong-wan, said the flight data recorder had "been deemed unrecoverable for data extraction domestically," so it was being sent to the U.S. for analysis in collaboration with the NTSB.
Joo said earlier that "the initial extraction has already been completed" for the cockpit voice recorder.
"Based on this preliminary data, we plan to start converting it into audio format," he told journalists, meaning investigators will likely soon be able to hear the pilots' communications during the ill-fated flight.
"I think the cockpit voice recorder, if they're able to read that out, that will be key to unlocking this mystery," Robert Sumwalt, former chair of the NTSB, told CBS News.
Jeju Air said the crash was not due to "any maintenance issues," according to South Korea's Yonhap news agency, and aviation expert Geoffrey Thomas told BBC News that South Korea's airlines were broadly deemed to follow "industry best practice" and that both the plane and Jeju Air had an "excellent safety record."
South Korean plane skidded into a fence shielding antennas
Transport Ministry officials said Monday that they would examine whether the fence the plane hit — a concrete structure which housed a set of antennas designed to guide aircraft safely during landings — should have been made with lighter materials that would break more easily upon impact. They said they were also trying to establish whether there were any communication problems between air traffic controllers and the pilot.
The positioning of the localizer antennas close to the end of the runway behind unforgiving fortifications will likely be a focus for investigators.
"Normally, on an airport with a runway at the end, you don't have a wall," Christian Beckert, a flight safety expert and pilot for German carrier Lufthansa told the Reuters news agency. "You more [often] have maybe an engineered material arresting system, which lets the airplane sink into the ground a little bit" to slow it down.
Could a bird strike have caused the Jeju Air disaster?
Lee Jeong-hyun, the chief of the local Muan fire department, said Sunday that a bird strike and bad weather could have contributed to the crash, but he stressed that the cause was still under investigation.
According to CBS News partner network BBC News, one passenger on the flight had messaged a relative before the disaster and said a bird "was stuck in the wing" and that it couldn't land, but officials have not yet confirmed whether there was any bird strike.
Geoffrey Thomas, the expert cited by BBC and the editor of Airline News, told Reuters separately that he was skeptical a bird strike alone could have caused the deadly crash.
"A bird strike is not unusual. Problems with an undercarriage are not unusual. Bird strikes happen far more often, but typically they don't cause the loss of an airplane by themselves," he said.
Why wasn't the landing gear deployed?
It remained unclear what, if any, engine or systems failures the flight crew might have been contending with in the last few minutes of the ill-fated flight. Experts have said video of the crash showed no apparent movement of the plane's flaps as it came down, which can help slow an aircraft, suggesting there could have been a loss of hydraulic pressure that controls the mechanical devices.
The hydraulic control systems operate independently, and experts said an engine problem would be unlikely to affect their operation.
The aircraft also has a manual override for pilots to lower landing gear in the event of an electronic or mechanical failure. It was unclear if the Jeju Air crew simply didn't have time to lower the nose wheels manually, or if some other factor could have prevented them from doing so.
Sumwalt, the former NTSB chair, told CBS News, "I flew 737s for 10 years as a captain, and I can say that the landing gear can be manually deployed, so the real question will be, what set up the sequence of events here? Did the bird strike set up the sequence of events where the crew got rushed and did not deploy the landing gear? I doubt that there was any sort of a malfunction with the gear, given that it can be deployed manually and through the normal means."
A long, hard year for U.S. aviation giant Boeing
The crash wrapped up a troubling 2024 for U.S. aviation giant Boeing, which has grappled with safety problems, a machinists strike and plunging stock prices.
Experts say the 737-800 aircraft is a more proven model than the company's much-maligned 737 Max jetliners, which were linked to fatal crashes in 2018 and 2019.
"I think it's very important to separate this crash ... from the issues that Boeing has had over the recent past," Sumwalt said. "This airplane is 15 years old, so it was probably not a manufacturing issue if the airplane is that old and flew thousands of hours. It's not a design issue. So I don't think that Boeing is going to take a direct hit because of this one."
Still, South Korean authorities said they'll conduct safety inspections on all the 737-800s operated by domestic airlines, including 39 by Jeju Air.
