Pratt & Whitney discovered nearly two years ago that one of its foreign business units had fraudulently adjusted test results on tens of thousands of engine parts to bypass additional inspection, the company said Monday.

Both Pratt and the federal government concluded in separate investigations that the safety of the parts was not compromised.

The unit, Carmel Forge Ltd. in Israel, changed test results for more than 40,000 forged disks over 15 years, Pratt said. In jet engines, the disks serve as hubs to which compressor and turbine blades are attached.

According to an internal company memo obtained by The Courant, Pratt launched an internal investigation in June 2011 after an employee tipped off the company to the problem.

The investigation confirmed the employee's information and led to an engineering review and metallurgical testing of the affected parts.

The review concluded that there was no impact on safety or durability of the parts made by Carmel Forge. "There have been no product recalls, service bulletins, or airworthiness directives, and there are no flight safety risks," Pratt spokeswoman Stephanie Duvall said Monday.

The internal memo to Pratt employees, dated Friday, said, "individuals at Carmel Forge produced test records that were not accurate. That is a serious matter, and we have treated it very seriously."

After its investigation, Pratt made personnel changes at the unit and added new software controls and testing equipment, the memo said.

Carmel Forge unit produces forgings for disks, seals and cases for engines and turbines, the memo said, and performs "all processes including raw material preparation, heat treating, semi-finished machining and testing."

United Technologies first listed the company as a subsidiary in 2000.

The discovery is the latest hiccup for the East Hartford engine maker in recent weeks. In late February, the military grounded its fleet of F-35s after examinations found a crack in a low-pressure turbine blade in Pratt's F135 engine. Also, the company said last week that it was reviewing five lines of its commercial and military engines with titanium parts that may not have met raw material specifications.