Bombardier Aerospace expressed “regrets” this week over a March 13, 2007, accident involving a Q400 turboprop at Japan’s Kochi Airport after the Japanese Aircraft and Railway Accidents Investigation Commission (JARAIC) found that a missing bolt caused the airplane’s nose landing gear door to jam, forcing a gear-up landing. None of the 60 passengers and crew aboard the ANA/Air Central flight sustained injuries in the accident.

The JARAIC’s final report concludes that Bombardier maintenance crew failed to install the bolt in question–located on the landing gear door operating linkage–during repair work in summer 2005, days after the airplane rolled off the assembly line. Workers had accidentally damaged the landing gear doors during testing on June 16, 2005, and replaced some of the components four days later. However, the missing bolt caused a bushing to slide out of position by about 1 centimeter, causing the landing gear door to jam against surrounding components.

The commission reached the conclusion that workers failed to attach the bolt during the repair work after finding no damage in the area that should have showed evidence of a dislodged bolt. According to the report, if Bombardier had specified tightening torque values for the bolt in its repair manual, workers could not have failed to install the part.

Japan’s transport ministry called on the Canadian authorities to urge the airplane manufacturer to strengthen its quality-control system. In a statement, Bombardier acknowledged the findings, and stressed that it has already taken action. 

“While the findings and recommendations contained in the final report are being reviewed, it should be noted that Bombardier has already implemented many of the recommendations proposed in the report during the course of the investigation,” the company said in a statement. “This includes the addition of further precautionary steps and documentation procedures in the assembly and repair process.”