Black Boxes Failed Minutes Before Jeju Air Crash

DALLAS — According to reports from Reuters, investigators have discovered that both black boxes, the Cockpit Voice Recorder (CVR) and the Flight Data Recorder (FDR) on Jeju Air (7C) Flight 7C2216, stopped recording approximately four minutes before the aircraft's fatal crash at South Korea's Muan International Airport (MWX) on December 29, 2024. 

On January 2, the South Korean transport ministry announced that the cockpit voice recorder was first analyzed domestically but without success before being sent to the U.S. National Transportation Safety Board (NTSB) laboratory after officials discovered missing data. 

“The damaged flight data recorder has been deemed irrecoverable for data extraction domestically,” said South Korean Deputy Minister for Civil Aviation Joo Jong-wan at the time. “It was agreed... to transport it to the United States for analysis in collaboration with the US National Transportation Safety Board.”

The Boeing 737-800 experienced difficulties during landing, ultimately striking a concrete structure and erupting into flames. Only two crew members in the aircraft's tail section, out of the 181 people aboard, survived the accident.

Amid the news of the 7C2216 CVR and FDR fails, South Korean Transport Minister Park Sang-woo has expressed his intention to resign, stating his sense of "heavy responsibility" for the disaster. The ministry has also pledged to enhance airport landing system safety following expert criticism of the runway's embankment design.

How Can Black Boxes Stop Recording?

Without going into speculation as to what happened on Flight 7C2216, black boxes can stop recording for several reasons:

1. Power failure: If the aircraft's electrical system fails, the black boxes may lose power and stop recording.
2. Physical damage: Severe impact or extreme conditions during a crash can damage the recording devices.
3. Technical malfunction: The devices themselves may experience internal failures or glitches.
4. Deliberate deactivation: In some cases, it may be possible for the cockpit crew to turn off certain recording devices, though this is not typical for modern commercial aircraft.
5. Data overwrite: Some older black boxes may overwrite data after a certain period, though modern devices are designed to record for the entire flight.

The last point reminds us of January of last year when the investigation of the Alaska Airlines (AS) Boeing 737-9 door plug blowout on Flight AS1282 found that the CVR was completely overwritten, meaning there was nothing on the CVR. The CVR overwrites every two hours, at least in the US, where this has happened before in previous incidents.

NTSB Chair Jennifer L. Homendy said she had "many times talked about the need to increase the time on CVRs from 2 hours to 25 hours, which is consistent with Europe and many other countries. The FAA has taken recent action to issue a notice of proposed rulemaking for such a time extension, but only on newly manufactured aircraft. The planes that are in service now have a life cycle of 40 to 50 years, meaning those planes will not have the time extension on their CVRs."

Ongoing Investigation

Investigators have confirmed that feathers were found in one of the recovered engines of the 7C Boeing 737-800, supporting the pilots' report of a bird strike approximately four minutes before the crash. However, that alone does not answer why the landing gear and flaps were not extended.

Available data suggests that the pilots did not radio air traffic control about a problem of this nature. This raises the question of whether the landing gear and flaps were missed on the pre-landing checklist for some reason or were malfunctioning.

Aircraft are designed to withstand heavy birdstrikes across the fuselage and in the engines. Furthermore, aircraft are designed to survive belly landings. If MWX was not equipped to handle emergencies of this nature, then why not divert to any number of nearby airports with longer runways?

The investigation continues with international cooperation between South Korean authorities, the NTSB, and Boeing. As per the Reuters report, “Investigators on Saturday compiled the complete transcript from the cockpit voice recorder recovered from the wreckage of the Jeju Air plane, and will discuss whether to disclose it or not.”

Furthermore, the police investigation has expanded to include the operators of 7C and MWX. Recent raids have been conducted at both facilities as authorities seek to understand the full circumstances leading to the deadliest plane crash on South Korean soil.