The crash of USAir Flight 427 is the troubled airline's fourth major plane crash in 3 1/2 years.
In a year with only two major airline crashes in the USA, USAir has had both of them.
The first was July 2 near Charlotte, N.C., when a USAir DC-9 went down during a thunderstorm killing 37. A wind burst is the suspected cause.
Once one of the airline industry's shining successes, USAir has had a variety of mishaps since its mid-1989 merger with Piedmont Airlines.
The USA's sixth-largest airline has lost $1.8 billion over the past five years. USAir is expected to lose more than $350 million before taxes this year.
Thursday's crash - the worst air disaster in the USA in seven years - will compound the problems.
The crash came hours after USAir held a news conference announcing a new business class service - a key to its bid to keep fliers from switching to new low-fare airlines.
Thursday's crash involved a twin-engine Boeing 737-300, the midsize member of the world's best-selling family of airliners. Boeing has delivered more than 2,600 737s since the model's introduction in 1967.
Boeing 737s have been involved in several major recent crashes. One of the most serious was on Oct. 19, 1988, when an Indian Airlines 737 crashed on final approach to Ahmadabad Airport, about 300 miles southwest of New Delhi, killing 130 of 135 aboard.
In 1988, an Aloha Airlines flight attendant was swept away when a 20-foot chunk of fuselage tore away from a 737 over the Pacific Ocean. The Federal Aviation Administration reacted by restricting older Boeing 737s from flying higher than 23,000 feet until they could be inspected.
