The Cessna went down at Charleroi airport when it developed a problem during takeoff and tried to return, a source told the Belgian newspaper De Standaard.
The Flandersnews.be news website reported the victims were members of one family -- a grandfather, his daughter-in-law and three grandchildren ages 7, 6 and 3, RIA Novosti said.
The cause of the crash had not been determined.
De Standaard said the crash forced the cancellation of five flights and delayed 16 others.
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