In this case, the 16 yr old girl was the wife's daughter by a previous relationship or marriage. The five kids who died were the joint progeny of both this father and mother, so all the father's line was wiped out by one crash.
I was in Beaver County that day at my in-laws. I'll never forget it. And the backstory on how that particular family wound up on Flight #427 is one of those "holy cow" moments involving such trivia as soccer practice, a TV show taping and available seating on the plane. Just a gut wrenching story even to this day.