Northwest Flight 188 pilots who over-flew their destination by more than 100 miles last Wednesday night told federal investigators on Sunday that getting lost in conversation—not falling asleep—is the reason why they ignored air-traffic controllers for more than an hour. Though consistent with their original statements, new information makes the pilots’ account more believable, reports The Wall Street Journal. It turns out their schedule wasn’t particularly full the day prior to the incident, and fatigue experts claim that the evening hours when they over-flew aren’t usually a risky time for pilots to fall asleep. “It was not a serious event, from a safety issue,” first officer Richard Cole told the Associated Press of the flight he shared with Captain Timothy Cheney. No formal reason has been cited and federal investigators will continue to explore whether fatigue was an issue.