Malaysia’s civil aviation chief has resigned after a new report shone light on his air-traffic control center’s failures during the mysterious disappearance of Flight 370 four years ago. The report released Monday raised the possibility that the jet may have been hijacked, but conceded there was no conclusive evidence of why the plane went off course and flew for more than seven hours after its last radio communication. Azharuddin Abdul Rahman said the report didn’t blame the civil aviation department for the plane’s loss but found that the Kuala Lumpur air-traffic control center failed to comply with some operating procedures. “Therefore, it is with regret and after much thought and contemplation that I have decided to resign as chairman of Civil Aviation Authority of Malaysia,” he said in his statement. The report said the investigation showed a failure to quickly initiate an emergency response and monitor radar continuously. The jet carrying 239 people from Kuala Lumpur to Beijing vanished March 8, 2014, and is presumed to have crashed in the Indian Ocean.