[CBC News] On the 30th, the Seoul Metropolitan Government sent a safety alert text message to inform residents that noise from aircraft flights may occur in the Gangnam-gu and Songpa-gu areas.

The city stated via text message, "Due to flights related to the Space Challenge event (hosted by the Air Force), flight noise may occur in the Gangnam-gu and Songpa-gu areas from 10:00 AM to around 4:30 PM today."

Accordingly, loud noises such as sonic booms from passing aircraft may be heard during these hours in Gangnam-gu, Songpa-gu, and nearby areas. This noise was identified as a result of flight activities related to the 'Space Challenge' event hosted by the Air Force.