5 killed, including 2 children, when plane crashes into homes

(CNN) -- A small plane crashed into two homes Tuesday in Sanford, Florida, near Orlando, killing five people -- the pilot, his passenger, and an adult and two children inside the houses. The two homes hit were reduced to smoking rubble. Only portions of their outside walls, blackened from the explosion and fire, remained standing. The fatalities include people from both homes -- a mother and her 6-month-old son in one home and a 4-year-old girl in the other, said Cleo Cohen, Sanford police spokeswoman. The 4-year-old's parents were taken to an Orlando hospital, and her brother, 10, was transferred to a Cincinnati, Ohio, burn center, Cohen said. He had third-degree burns over 80 to 90 percent of his body, according to Sanford Fire Department investigator Matt Minnetto. Michael Klemm was piloting the plane, Cohen said. Klemm was a senior captain with NASCAR Aviation, a statement from NASCAR said. The passenger, Dr. Bruce Kennedy, was the husband of International Speedway Corp. President Lesa France Kennedy. She is the daughter of the longtime head of NASCAR, Bill France Jr., who died in June. One off-duty firefighter was treated for smoke inhalation, Cohen told reporters. In a written statement, Florida Gov. Charlie Crist thanked that firefighter, whom he identified as Ryan Cooper. Crist said he joins Floridians in prayer and grief for the families of those killed. "My heart goes out to my friend Dr. Bruce Kennedy and all involved with this terrible incident," he said. "Bruce was a great friend and a great doctor from an outstanding family. He was gracious beyond words, and his death is a terrible loss for Florida." The twin-engine Cessna 310, registered to Competitor Liaison Bureau, had taken off from Daytona Beach, Florida, heading to Lakeland, Florida. It declared an emergency with smoke in the cockpit and was attempting to land at Orlando Sanford International Airport, said Federal Aviation Administration spokeswoman Kathleen Bergen. Instead, the plane crashed about five miles from the airport in a neighborhood called The Preserve at Lake Monroe. "First I heard a plane flying overhead. It sounded like a semi-truck coming down the road trying to slow down. As soon as it hit, it exploded into flames," a witness told CNN affiliate WESH 2 News. "A boy jumped out of the second story. He was on fire and extinguished himself. The wife ran out of the front door. She was on fire. Someone was screaming about a baby still inside the house," a witness told WESH