Granted I made some obvious assumptions. For instance in the USA we are in business to make money as people are elsewhere. Often money is spent on the lowest bidder, or what looks like the best deal. I would assume that the Japanese would have tried to make the best deal for them. Sometimes a deal looks good on paper and seems to make good business sense. Japan may have been stuck with some lemons from Canada. Japan might also have some bad maintenance practices. However, they seem to have recently purchased the planes. 2003-present being fairly recent for airframes. Planes less than 10 years old are considered fairly new. Just look at the chinook, and some of our older military aircraft.
Since many facts and figures were not provided it is hard to say otherwise. It is noted that:
"The Transport Ministry ordered emergency inspections for all 36 Bombardier DHC-8s in use in Japan, citing possible defects with the model's landing gear, according to ministry official Yasuo Ishii."
This means someone is conducting some kind of Official Investigation into the matter. It is thought that the landing Gear or the system that makes the landing gear come down and lock may be defective.
Americans have had their own safety problems in the past. However, this may be indicitive of a poorly designed ariplane, or one that was not fully tested. If one or two planes has a problem it might be maintenance. However, I would think from a realistic perspective, that a country that is an Island surrounded by water, would want the planes to be able to be a little more dependable. There is not a lot of open land in Japan to crash land planes.
