Okanogan County Fire District 6 says a helicopter toppled after landing on a snow bank in Winthrop on Saturday. Fire officials say the wreck happened near an ice rink. Okanogan County Sheriff Tony Hawley says mechanical problems forced the helicopter to descend onto the ground. Authorities say pilot and the passenger were not hurt; there were no fuel leaks. The aircraft was owned by Highline Helicopters out of Darrington, Washington. Hawley says the aircraft was putting tracking collars on deer. The helicopter may have been contracted by Fish and Wildlife to put tracking collars on mule deer as part of a migration study. The Federal Aviation Administration has secured the area and is investigating the crash.