Kevin McCorry reports that another former Philadelphia School District principal has been charged in the test cheating scandal. In our next episode of “The Philly Index,” Holly Otterbein looks at Mayor Michael Nutter’s handling of the city’s prison system. Tom MacDonald hears from Constitution Center officials about their upcoming change of board chair. Dave Davies talks with Philadelphia mayoral candidate Ken Trujillo. On Story Corner, Rabbi Linda Holtzman tells about deciding between two conflicting promises she’s made.