BOSTON -- A light twin-engine cargo plane took a wrong turn, hit a house and exploded in a fireball, killing the pilot and sparking an inferno that burned three homes and seriously injured three people.

The Piper Seneca hit the top of at least one three-story house in the Dorchester section at 1:12 a.m. before crashing in Lonsdale Street, said Fire Capt. Matthew Corbett. The resulting nine-alarm blaze sent residents fleeing and took three hours to extinguish.

The pilot took a "mysterious left turn" off course about 4 miles from Logan International Airport, said Mike Ciccarelli, a spokesman for the Federal Aviation Administration. "The Logan tower then lost all radar and radio contact with the aircraft."

"The whole street was like an inferno," said Mayor Raymond L. Flynn, who helped evacuate homes just minutes after the crash. "Eight automobiles were engulfed in flames."

The plane struck a "triple-decker" house and gasoline from the aircraft splashed onto two other homes, fueling the blaze that gutted all three buildings and destroyed several cars. Damage from the accident was estimated at $2 million.

The badly burned pilot, the only person aboard the plane, was dragged from the plane by firefighters, but they were unable to save him.

The freight plane, owned by Cash Air of Lawrence, Mass., had originated in Teterboro, N.J., Ciccarelli said.