TOKYO: Japan’s new passenger jet on Sunday aborted a test flight to the United States for the second time in two days because of an air conditioning defect, its maker said. On Saturday, a Mitsubishi Regional Jet left Nagoya airport in central Japan for the US but soon turned back because of air-conditioning problems. The plane took off again on Sunday but problems “in the same air-conditioning monitoring system” caused it to return, Mitsubishi Heavy and its subsidiary Mitsubishi Aircraft said in a joint statement. “After the jet returned yesterday, we checked the system and changed parts. After confirming that there was no problem in a test on the ground, today we launched the flight again, but the same problem occurred,” company spokesman Yuji Sawamura told Agence-France Presse. The development of the MRJ, Japan’s first domestically produced passenger jet for over half a century, has suffered a series of delays.