Mitsubishi Electric Corp.'s sign is seen in front of the building that houses the company's headquarters in Tokyo's Chiyoda Ward on June 30, 2021. (Mainichi/Takehiko Onishi)

       TOKYO -- Mitsubishi Electric Corp.'s train air conditioner plant in Nagasaki Prefecture has been fabricating product inspection data since at least 1985 using software created in-house, a source familiar with the matter said on June 30.

       The software made it appear that air conditioning units had been inspected by filling in inspection certificates with fabricated figures. That the program has been in use for decades has raised suspicions that Mitsubishi Electric knowingly and systematically engaged in inappropriate inspection practices.

       According to the source, the program automatically outputs figures above the minimum standards when the inspection form is being filled in with dates and product information. It is designed to output different values depending on the product to avoid hints of contrivance, allowing the company to pretend it has properly completed the inspections. That the software is designed to make fictionalizing the figures easy suggests the company may have been engaged in inspection data fabrication since before the program was created.

       Mitsubishi Electric has supplied train car air conditioners to railway companies across Japan, including the Japan Railway group and other private train operators, as well as subway and high-speed train operators in Europe and the United States.

       Mitsubishi Electric was contractually obligated to check the units' temperature and humidity control performance, as well as energy efficiency, waterproofing, voltage fluctuation durability and other features designated by customers. However, the company omitted inspections or conducted them under conditions different from those specified by customers. The practices have apparently been in use since at least 1985.

       According to the company, a total of some 84,600 products with possible inspection data problems have been shipped.

       (Japanese original by Ryotaro Ikawa, Business News Department)

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