The pilot was identified as Al Lavender, a former city councillor and mayor of Newburyport, police said.
There were no reported injuries to residents of the building, located in Methuen across the Merrimack River from Lawrence Municipal Airport and about 20 miles southwest of Newburyport.
The Federal Aviation Administration said the home-built plane was on its final approach when it crashed. Only a few people were inside the building at the Prides Crossing condominium complex when the plane crashed shortly after 1 pm, Lt Stephen Smith said.
"It looked like it took a nosedive out of the blue and smashed into the building," Lontine said.