A Mitsubishi Regional Jet left Nagoya Airport for the United States on Monday to complete flight tests that were pre-empted twice about a month ago by problems with its air-conditioning system.

Mired in development delays, the MRJ, intended to be the nation's first domestically produced passenger jet, left Nagoya at around 1:30 p.m. It made its first stop at New Chitose Airport, near Sapporo, later in the day.

After leaving Hokkaido, it is scheduled to make refueling stops in Russia and Alaska before arriving at Grant County International Airport in Washington state in a few days, according to Mitsubishi Aircraft Corp., a subsidiary of Mitsubishi Heavy Industries Ltd.

The plane is designed for short- to medium-haul flights, but late last month, on two consecutive days, the MRJ left Nagoya to conduct the crucial U.S. tests needed for certification only to turn back because of problems with the air-conditioning system.

The MRJ's development has been delayed at least four time due to changes in the design, manufacturing process and parts.