Black box records missing

[Anchor]

In this incident, the aircraft's black box records for the last 4 minutes before the collision are unusually missing.

The investigation revealed that there was no emergency backup battery in the black box.

Currently, more than half of the same model aircraft in the country are also in the same situation.

Reporter Lee Seung-cheol has the details.

[Report]

According to the Ministry of Land, Infrastructure and Transport, the black box of the accident aircraft stopped recording around 8:59 AM, when the pilot shouted mayday and attempted to return.

The most critical '4 minutes' of communication between the pilots, as well as flight data, have disappeared.

Originally, the flight data recorder (FDR) of the black box receives power from the left engine, while the cockpit voice recorder (CVR) receives power from the right engine.

Even if the right engine shuts down due to a bird strike, the FDR and CVR continue to record by receiving power from the left engine.

If the left engine also shuts down, the backup battery for the CVR provides power for about 10 minutes.

However, this backup battery has been mandatory since 2018.

The Ministry confirmed that the accident aircraft was manufactured in 2009 and did not have a backup battery for the CVR.

Still, questions remain about the 'missing 4 minutes.'

This is because there is a main battery that supplies power for more than 30 minutes even if the engines are off.

In fact, the Ministry has stated that communication occurred between the pilot and the air traffic controller at the time the black box recording stopped.

[Yoo Kyung-soo/Director of Aviation Safety Policy, Ministry of Land, Infrastructure and Transport/Jan. 1: "We confirmed that there was communication in an unstable situation, and that there was a final air traffic controller's permission."]

The Ministry explained that although there are two main batteries, they only supply power for minimal communication and control, and do not provide power to the black box.

[Shim Jae-dong/Professor, Department of Aviation Maintenance, Sehan University: "(With) two batteries, an aircraft can stay in the air for an hour. During this time, you need communication. The minimal power used for mayday calls and such is still operational."]

As a result of a comprehensive investigation by the ministry, it was found that more than half of the 101 aircraft of the same model as the accident aircraft do not have a backup battery.

With the disappearance of the black box records, the limitations on the accident investigation have increased, making disputes over the cause and responsibility inevitable.

This is Lee Seung-cheol from KBS News.