The Coast Guard is searching for a tour helicopter that disappeared in Hawaii with seven people aboard. Authorities say the helicopter’s owner called for help about 45 minutes after the chopper was due back from a tour of Kauai’s Na Pali Coast on Thursday evening. Two of the passengers are believed to be minors. Steep terrain, low visibility, choppy seas and rain complicated the search effort. The helicopter has an electronic locator, but no signals have been received. A Federal Aviation Administration spokesman says the Eurocopter took off from the town of Lihue.