WASHINGTON — Federal investigators say pilots who were killed when their UPS cargo plane crashed during a landing attempt in Birmingham, Alabama, last year made a series of errors, and may have been suffering from fatigue.The plane crashed onAug. 14, 2013 and was en route from Louisville,where UPS has its air hub. Two crew members, Captain Cerea Beal, Jr. and First Officer Shanda Fanning, died in the crash.The investigators also conclude that more stringent regulations on hours of work for pilots wouldn't have prevented the accident.Investigators are telling the National Transportation Safety Board Tuesday that the pilots of Flight 1354 incorrectly programmed the plane's flight management computer, descended too fast, failed to call out altitude levels and didn't abort the landing when they realized they weren't lined up properly.