The National Transportation Safety Board was preparing to release several reports on the crash of Delta Flight 1141 Monday, but a report about the setting of the jet's wing flaps was not to be among them.

Safety board officials say the reports fall short of answering questions about the crash that killed 14. "We just don't have the answers yet," said Lee Dickinson Jr., National Transportation Safety Board member. "This is one of the most difficult crashes we have investigated."The Salt Lake-bound Delta Air Lines Boeing 727 crashed on takeoff Aug. 31 at Dallas-Fort Worth International Airport after struggling 30 feet above the runway for more than a mile. Ninety-four people survived.

Safety board investigators attributed their lack of solid answers to an antiquated flight data recorder, contradictory evidence and the inability of the cockpit crew to remember details of the crash.

"Usually 60 days after a crash, we have a pretty good idea what happened and are waiting only for the analysis of the evidence to bear us out," Dickinson said. "This time, we've got a lot of contradictions that make it a real challenge."