A Delta Air Lines captain who is an expert on windshear is scheduled to take the stand in federal court Monday when Delta continues its case against the government in the 1985 crash of Delta Flight 191.

As a safety official for the Air Line Pilots Association, the witness, William Melvin, has studied the storm-spawned wind phenomenon blamed for the crash.

Flight 191 crashed Aug. 2, 1985, killing 137 people and injuring 25, as it attempted to land at Dallas/Fort Worth Airport during a severe thunderstorm.

Delta, which was the target of about 100 crash-related suits, in turn sued the federal government, seeking a contribution toward more than $100 million in damages it expects to eventually pay in connection with the crash.

U.S. District Judge David O. Belew Jr. must determine liability for the crash between the two parties in the non-jury trial. Belew will hold a separate trial to determine the amount of damages.

A majority of the individual suits against the airline have been tried or settled out of court. But 26 suits seeking punitive damages against the airline remain unresolved. The first punitive case, representing up to four plaintiffs, is also to be tried in Belew's court.