Maine State Police said a pilot walked away uninjured when his plane veered off a runway, hit a snowbank, and came to rest upside down at the Norridgewock Airport. Troopers said 44-year-old Robert Lewandowski of Winthrop told them he was making practice landings Monday when a mechanical failure caused his plane to veer out of control. The plane was moved to a nearby hangar for assessment. Federal officials will investigate.