A commuter plane taking off in clear weather Wednesday veered sharply back toward the airport and crashed into the side of a hangar, bursting into flames and killing all 21 people aboard.

The cause of the nation's first deadly airline accident in more than a year was not immediately clear.

US Airways Express Flight 5481 hit the corner of the hangar at full throttle moments after leaving Charlotte-Douglas International Airport for Greer, S.C., officials said. No one on the ground was injured.

Hours later, smoke poured from the wreckage of the Beech 1900 twin-engine turboprop near a scorched, battered corner of the US Airways maintenance hangar.

"The plane is so destroyed there's not much to see," police spokesman Keith Bridges said. "It's just a horrible sight."

The plane, carrying 19 passengers and two crew members, had taken off to the south, then cut back sharply back toward the airport, airport director Jerry Orr said.

The pilot, Katie Leslie, contacted the tower to report an emergency, said Greg Martin, a spokesman for the Federal Aviation Administration. But the transmission was cut short and the emergency was never identified, he said.

The National Transportation Safety Board sent investigators. The FBI said there were no immediate indications of terrorism.

The weather at the airport was clear at the time, with winds of only 8 mph, said Rodney Hinson, a National Weather Service meteorologist. The flight was to be a short one, covering only 80 miles.

The 8-year-old plane was operated by Mesa Air Lines under the US Airways Express name. It had flown 15,000 hours and performed 21,000 takeoffs and landings.

FAA records show the aircraft reported service difficulties 10 times, most of them minor. In November, the company reported a leaking fuel pump that was replaced. In May, the left main landing gear wouldn't retract during takeoff; the plane landed safely and a hydraulic power pack was replaced.

The FAA has issued nearly two dozen airworthiness directives on the 1900-D since 1994. The directives warn of problems that must be repaired if found in an aircraft.

A maintenance alert for twin-engine Beech 1900 turboprops issued in August said attachment bolts for the vertical stabilizer were found loose on one plane. And a directive issued in November and scheduled to be effective in two days warned that screws could come loose and interfere with the horizontal stabilizer.

There have been eight fatal accidents involving Beech 1900s in 40 years, according to NTSB records. Three people were killed in the most recent crash of a Beech 1900C, in Eagleton, Ark., on Dec. 9.

The Charlotte crash came after a year in which there were no deaths aboard a passenger or cargo airliner in the United States. The last fatal crash was that of an American Airlines jetliner in New York City on Nov. 12, 2001, in which 265 people died.

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Details on the Air Midwest plane involved in Wednesday's crash at Charlotte, N.C.:

• Beechcraft 1900D, built by Raytheon Aircraft Co.

• Twin-engine turboprop.

• Capacity of 12 to 19 passengers, plus two crew members.
  
• Range of about 1,400 nautical miles at speed of 327 mph.

• Eight-year-old plane was one of about 50 operated by Mesa Air Lines, parent of Air Midwest.

• Plane had been flown 15,000 hours and 21,000 takeoffs and landings.

• FAA records showed service difficulties including a leaking fuel pump that was replaced last fall, landing gear that wouldn't retract in May, and several minor mechanical problems.

• A maintenance alert issued in August for the 1900D said vertical stabilizer attachment bolts were found loose on another aircraft. FAA records did not say if the Air Midwest plane's stabilizer was checked after that alert, and company records were not immediately available.

Source: The Associated Press contributed to this report.