BY  Steve Marshall; Robert Davis

        ALIQUIPPA, Pa. - Billowing smoke, scattered baggage and smoldering bits of fuselage were all that remained Thursday of USAir Flight 427.
        Officials said there were no survivors from the plane and no indication anyone on the ground was hurt.
        Veteran pilots were at a loss to explain the crash.
        "It's puzzling, very deeply puzzling to me and to other pilots," said John Nance, a pilot, author and consultant.
        "It's devastating," said orthopedic surgeon Trent Gause, who responded to the scene. "There is no plane; there are just scattered parts everywhere. It's terrible. It's terrible. It's terrible."
        The flight crashed at 7:19 p.m. ET as it was attempting a landing at Greater Pittsburgh International Airport.
        The Boeing 737, built in 1987, passed a routine safety inspection in Hartford, Conn., Wednesday night, USAir says.
        Witnesses reported a gruesome scene of carnage in a clearing on a hillside so heavily wooded that emergency workers' lights could illuminate only a small area at a time.
        "All we saw was body parts hanging from the trees," said Denise Godich, a nurse who went to the scene.
        "The heat and smoke were so intense you couldn't see anything," said Linda Dickhart, who lives less than a mile from the scene. "I thought it was coming . . . through my roof."
        After the accident, 20 emergency vehicles were on top of the hill, and a medical helicopter hovered above.
        Authorities were setting up a morgue at the airport, according to Arthur Gilkes, solicitor for the Allegheny County Coroner's Office.
        "There's no indication at all as to what caused the accident," said USAir assistant vice president Dave Shipley. "There's no question the 737 is a completely safe airplane." The pilots were experienced in flying the craft, he said.
        The plane, en route from Chicago's O'Hare International Airport to Pittsburgh, apparently went down six miles from the airport, about 20 miles northwest of Pittsburgh in Aliquippa. Officials closed all roads leading there.
        The plane was to continue to West Palm Beach, Fla., as Flight 8961. It was to arrive at 10:27 p.m.
        In Florida, family members waiting for loved ones panicked as they heard the news.
        Lou and Fran Renzie of Stuart were expecting their nephew from Chicago on USAir and they panicked when they heard the news on TV.
        "I was so scared I started shaking," said Lou Renzie. "Then we found out he came through Charlotte, not Pittsburgh."
        "We're relieved for us but heartbroken for the others," said Fran Renzie.
        Eyewitness Sandra Zuback told CNN: "We heard the plane flying low overhead. The plane just shut off and went down. It just crashed."
        Pittsburgh International has had only one previous fatal accident, the April 1, 1956, crash of a TWA Martin 404 propeller airliner that killed 22 and injured 14.
        WTAE-TV in Pittsburgh quoted witness Kauline Brown, who saw the crash from her car, as saying: "I looked up and it was right over my car. My daughter was screaming. My God, it could have just come down and hit other cars. It was going pretty fast, nose down. There was a loud boom and a lot of black smoke."
        Lisa Howard, a spokeswoman for Chicago's Department of Aviation, said the city has offered to set up a center for the families of any victims.
        Counseling was made available to families of victims in Pittsburgh as well, said Pat Boyle, the Pittsburgh airport operations director.
        Lorraine Dean of Aliquippa, a USAir secretary, was shopping at a nearby plaza when the plane crashed.
        "Half the people around here (at the shopping center) are from the company. If there is something we can do, we will. We are all praying. It's the worst thing you can imagine."

AIR DISASTERS Major U.S. plane crashes in the past decade:
        -- July 2: USAir jet in thunderstorm near North Carolina's Charlotte-Douglas International Airport killing 37 of 57 on board.
        -- March 22, 1992: USAir jet during takeoff in a snowstorm at New York's La Guardia Airport, killing 27.
        -- March 3, 1991: United Airlines jet crashes near Colorado Springs airport, killing 25.
        -- Feb. 1, 1991: USAir jetliner and commuter plane collide on Los Angeles runway; 34 killed.
        -- Jan. 25, 1990: Avianca Boeing 707 crashes in Cove Neck, N.Y., after running out of fuel. Of the 159 people aboard, 73 died.
        -- July 19, 1989: United Airlines DC-10 crashes during emergency landing at Sioux City, Iowa, killing 112 of the 296 aboard.
        -- Aug. 31, 1988: Delta Airlines Boeing 727 crashes on takeoff at Dallas Fort-Worth Airport, killing 14.
        -- Dec. 7, 1987: Pacific Southwest jet crashes near Paso Robles, Calif., killing 43. Gunfire heard on cockpit recorder leads authorities to conclude a vengeful ex-employee of PSA's parent company caused crash.
        -- Nov. 15, 1987: Continental Airlines jet crashes on takeoff at Denver's Stapleton International Airport, killing 28.
        -- Aug. 16, 1987: Northwest Airlines jet crashes on takeoff at Detroit Metropolitan Airport; 156 killed.
        -- Aug. 31, 1986: Aeromexico DC-9 and small plane collide over Cerritos, Calif., killing 82, including 15 on the ground.
        -- Sept. 6, 1985: Midwest Express Airlines jet crashes after takeoff from Milwaukee's Mitchell Field, killing 31.
        -- Aug. 2, 1985: Delta Airlines jet crashes at Dallas-Fort Worth International Airport, killing 137.

The last minutes of Flight 427 USAir Flight 427 carrying 131 people crashed nose down in a heavily wooded area six miles north of Pittsburgh International Airport as it was trying to land. Officials said there were no survivors. Where the plane, en route from Chicago to Pittsburgh and then West Palm Beach, Fla., crashed:
        -- At about 7 p.m., pilot radioed controllers that the twin-engine Boeing 737 was on final approach `at 6,000 feet,' says FAA's Donald Perry.
        -- At 7:19 p.m., Perry says `air traffic control lost radar and radio contact.'
        -- Cause of crash is unknown; weather was clear at the time. One eyewitness said the plane turned to the right, then appeared to turn over once or twice before going gown.
        -- Other eyewitnesses say they heard an explosion and a `thud' before hearing a crash.

Boeing 737-300
        -- Accommodates up to 149 passengers
        -- More than 2,600 put into service
        -- Is the most popular commercial plane model ever developed. Contributing: Steve Smiley in Aliquippa and Maria Puente