A Boeing-737 passenger jet operated by the low-cost airline, FlyDubai, has crashed on landing in the Russian city of Rostov-on-Don, in the south of the country.All sixty-one people on board were killed when the plane crashed and burst into flames on Saturday morning, a local official said.“A Boeing 737 crashed as it was coming into land. There were 61 people on board. They are all dead,” said a spokesman from the local ministry, quoted by the official TASS news agency.There were 55 passengers and six crew members on the plane, the official added.The accident happened at 0050 GMT, according to an official statement from the emergencies ministry