PHILADELPHIA (AP) — A medical transport jet carrying a child patient, her mother and four others has crashed into a Philadelphia neighborhood about 30 seconds after taking off, erupting in a fireball and engulfing several homes in flames. All six people aboard were from Mexico. The child had been treated in Philadelphia for a life-threatening condition and was being transported home. The crash comes two days after the country’s deadliest aviation disaster in almost a quarter century, in Washington, D.C.