The transport ministry urged Skymark Airlines to improve operations Tuesday after finding several problems during a recent inspection, including noncompliance of a rule requiring a pilot to don an oxygen mask if the other pilot leaves the cockpit in flight, and poor English skills of cabin attendants.
It is the second disciplinary step the Land, Transport, Infrastructure and Tourism Ministry has taken against the budget carrier since issuing a similar warning in 2006 for its failure to properly conduct aircraft maintenance.
"We want the airline to take the warning seriously as problems have been found in each of the areas of safety control, flight operations and maintenance," transport minister Seiji Maehara said.
The ministry urged the carrier to submit a business improvement plan by April 13.
According to the latest findings, Skymark's pilots were not following a procedure requiring a pilot to put on an oxygen mask if the other pilot leaves the cockpit for any reason, to avoid loss of control in the event of an emergency depressurization when flying at altitudes at or above 3,000 meters.
The ministry also found that cabin attendants failed to respond to calls by non-Japanese pilots due to their poor English proficiency.
The carrier cut the number of cabin attendants assigned to explain onboard safety equipment before takeoff to two from three, resulting in cases where passengers could not see them.
The problems related to cabin attendants were raised in internal Skymark meetings, but the firm did not take any action on the issue.
The ministry's latest warning came after it carried out an unusually lengthy three weeks of inspection of the carrier from mid-March.