The transport ministry on Monday inspected the headquarters of Skymark Airlines Co. in connection with the carrier's failure to repair an aircraft as scheduled and at a time of apparent disarray in its maintenance forces.

The ministry sent a team of seven officials to Skymark's headquarters in Minato Ward to have them check maintenance-related documents and question airline officials.

More than 10 aircraft mechanics have quit Skymark in the past 12 months or so. The chief of the maintenance department resigned in December and Vice Chairman Takashi Ide is doubling as maintenance chief.

The plane in question had been flown for nine months beyond its scheduled repair date before the oversight was discovered by an employee on March 9. The airline notified the ministry about the mistake the next day.

In a visit to Skymark headquarters Monday, Tokushima Vice Gov. Mahashiro Kimura called on the airline to improve its safety measures.

Kimura made the request in connection with the discovery Friday that Skymark continued flying a Boeing 767 the previous day even though it had been struck by lightning after arriving at Tokushima airport.

An inspection at the airport showed nothing was wrong with the plane -- which happened to be the same one that was denied the scheduled repair work -- and it departed for Haneda. But another inspection carried out in Tokyo showed that a rivet under a door had in fact melted. None of the crew or 132 passengers on board was injured.

Established in 1996, the airline operates flights linking Tokyo with Fukuoka, Osaka, Kagoshima and Tokushima.