Three persons were killed when a small aircraft crashed into the backyard of a home in the Brazilian state of Sao Paulo, officials said.The Beechcraft plane ended up nose down next to the swimming pool behind the house in Sao Jose do Rio Preto, some 440 km (273 miles) from Sao Paulo city on Monday, Efe news reported.While the home was damaged, nobody on the ground was hurt, firefighters said.The plane crashed on the approach to the airport in San Jose do Rio Preto, according to authorities, who said that the causes of the accident were not yet known.