A Philadelphia father is calling his son a “superhero” for shielding his younger sister when a medevac jet crashed in a Philadelphia neighborhood, showering flames and debris on homes and the vehicle in which the family was riding.

Four of the 24 people injured after the Northeast Philadelphia plane crash remain hospitalized Two are now stable, and two remain in critical condition.

The impact area where a medical plane crashed in Philadelphia was notably “expansive,” U.S. Transportation Secretary Sean Duffy said Monday after viewing the site.