A passenger jet being developed by Mitsubishi Aircraft Corp. aborted its second attempt to head to the United States on Sunday when an air conditioning problem that thwarted its first bid reoccurred.

The Mitsubishi Regional Jet, which has been mired in a series of development delays, left Nagoya at around 1 p.m. for Hokkaido, its first planned stop. But it was forced to turn around two hours later, according to Mitsubishi Aircraft, a subsidiary of Mitsubishi Heavy Industries Ltd.

The company said it has not decided when the jet will make the next attempt to fly to the U.S. as it needs to identify the cause of the problem.

Mitsubishi Heavy aimed to take the MRJ to the U.S. for certification testing by the end of this month.

The aircraft, designed for short- to medium-haul flights, first set off from Nagoya on Saturday headed for the Grant County International Airport in Washington State, where the tests will take place. It was scheduled to make refueling stops in Russia and Alaska.

The development of the MRJ, Japan's first domestically produced passenger jet, has suffered a series of delays due to changes in the design, manufacturing process and parts.