A light plane that crashed onto a tennis court and exploded may have experienced trouble with an oil line before slamming to the ground, killing a Canadian family of five, the pilot's brother said Saturday.

The twin-engine, six-seat Piper Aerostar PA-60 crashed onto the court at the Newport Beach Tennis Club shortly after taking off from John Wayne Airport Friday morning.The pilot's brother, a police officer in Medicine Hat, Alberta, said Newport Beach police told him the plane was serviced earlier in the week at one of the airport's repair shops after developing an oil line problem.