Japan Airlines apologized Wednesday over a series of flight delays caused by drunken pilots, following a reprimand from the transport ministry.

There have been at least three cases in the past year or so in which a pilot failed to pass a pre-flight alcohol test or was reported to the police for loud, drunken behavior.

“We take this situation seriously, especially since we had already been given a business improvement order last December and had been in the process of implementing countermeasures,” JAL President Mitsuko Tottori told a news conference Wednesday.