Mitsubishi Materials Corporation (MMC) has admitted its subsidiaries falsified data about products, including parts for aircraft and vehicles—the latest in a series of quality assurance scandals involving Japanese manufacturers.
The company said three divisions—Mitsubishi Cable, Mitsubishi Shindoh and Mitsubishi Aluminium— faked data for products supplied to the aerospace, car and electric power industries.
Between April 2015 and September this year, US$254m worth of products were shipped from MMC's Wakayama plant to 229 companies, including 70 in the aerospace industry and seven car makers.
At Mitsubishi Cable, specification data on its O-ring sealing product—commonly used in joining pipes to prevent oil, water and air from leaking—were altered to match those requested by client companies.
Since October 2016, Mitsubishi Shindoh falsified data on brass strips and copper products from its Fukushima plant worth $1.04bn, which were supplied to 29 companies in the automotive and electronics industries.
Mitsubishi Aluminium also supplied products with falsified specification data but it and client firms have confirmed that they are safe for continual use, the company said, adding that its investigation has not uncovered any cases that raise the possibility of legal violations or safety issues.
A spokesman at the Acquisition, Technology and Logistics Agency under Japan’s Ministry of Defense said products including rubber seals not meeting requested specification from Mitsubishi Cable were installed in hydraulic components of Self-Defence Force aircraft and ship engines.
He added that Mitsubishi Cable told the agency that any impact on the performance of the products in question is not serious enough to require an immediate suspension of operation.
Boeing Co, who also buys products from Mitsubishi Materials for its aircrafts, said it is reviewing the matter.
MMC has now suspended delivery of all non-conforming products from its plants and set up a task force to look into the problems and devise countermeasures to improve quality control.
Naoki Ono, executive vice president of MMC, said the company would provide an update on its investigation by the end of the year.
“My duty is to instruct and supervise the investigation of the causes and to take preventive measures swiftly,” he said.
He said Mitsubishi Cable uncovered the falsification in February, stopped shipping affected products on 23 October and told its parent company two days later. Mitsubishi Shindoh found out about its problem in October, stopped shipments on 18 October and alerted MMC the following day.
Akira Takeuchi, MMC president, apologised to clients and stakeholders and said that the company did not disclose the problem when it reported earnings earlier this month because it wanted to find all of the customers affected.
This latest scandal comes in the wake of another data-falsification scandal involving joint venture partner Kobe Steel, which found that Mitsubishi Heavy Industries had inappropriately distorted data for rubber sealing products, used in aircrafts and cars.
Kobe Steel, Japan’s third largest steelmaker, admitted in October that workers tampered with product specification, shaking up global supply chains and forcing global automakers, aircraft manufacturers and other companies to check whether the safety or performance of their products had been compromised.
Although 525 customers were affected, none have reported safety issues and no products have been recalled. So far, shipments to 484 clients have been given the all clear, Kobe Steel said.
MMC has a 45% share in copper tube joint venture with Kobe Steel, including the Hatano plant that is at the centre of Kobe’s data-falsification scandal.
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