After a safety inspection involving 101 Boeing 737-800 aircraft, the same model involved in December’s Jeju Air tragedy, the transport ministry has uncovered violations.

The ministry announced on Monday that after checking maintenance records for major systems such as landing gear and engines, as well as compliance with maintenance procedures, it found that safety regulations were generally followed.

But the ministry also learned that inspections were not always carried out on time and filters were not always replaced when necessary. 

The ministry said it plans to take stern action under relevant laws and will also improve emergency procedures, possibly by adding bird strike response strategies to pre-flight briefings.

The safety inspection took place from December 30 to January 10 and targeted aircraft owned by six domestic airlines.