HARTFORD—Pilot error probably caused the 2019 crash of a World War II-era bomber in Connecticut that killed seven people and wounded six others, the National Transportation Safety Board said in a report released Tuesday. It cited inadequate maintenance as a contributing factor. The four-engine, propeller-driven B-17G Flying Fortress bomber with 13 people aboard crashed at Bradley International Airport, north of Hartford, during a traveling vintage aircraft show on Oct. 2, 2019. The pilot, Ernest “Mac” McCauley, reported a problem with one of the engines shortly after takeoff, and the plane crashed into a maintenance building and burst into flames during a landing attempt. The NTSB said the flight data indicated that the landing gear was extended too early, adding drag that slowed the plane, and it was traveling too slow on its return to the airport. “The B-17 could likely have overflown the approach lights and landed on the runway …