A medical jet with seven Mexican nationals on board crashed into a busy Philadelphia neighbourhood on Friday, authorities said, marking another US aviation disaster after a passenger plane and a military helicopter collided midair in Washington earlier this week. Video footage appeared to show the twin-engine plane descending at a sharp angle towards a residential area, sparking a huge fireball upon impact and showering wreckage over homes and vehicles. The Federal Aviation Administration (FAA) said the aircraft was a Learjet 55 – an American-French business jet – that had taken off shortly before from Northeast Philadelphia Airport bound for Branson, Missouri. The crash happened just after 6pm (4am PKT). A young girl who had been in the United States for medical care, her mother, and members of the flight and medical crews accompanying her onboard were killed in the crash, the children’s hospital that treated her told AFP.