Japanese heavy machinery maker IHI Corporation says it has found that thousands of improper inspections were carried out during the process of manufacturing aircraft engine parts.
The company says an in-house investigation uncovered 7,138 cases of misconduct over a two-year period at three of its domestic plants.
Company officials said uncertified workers conducted the inspections and prepared inspection records.
The officials said the parts underwent similar checks during a different process, so they are safe.
They added that the engine parts in question were used in aircraft shipped to the Self-Defense Forces, domestic and foreign airlines, and other organizations.
Late last month, the industry ministry ordered IHI to rectify its business practices following a maintenance work scandal.
The scandal involved 6,340 cases of improper inspections carried out during maintenance work on aircraft engines.
IHI said it is taking this matter very seriously and will make sure that it does not happen again.