A passenger plane with 112 people on board has crashed at Kisangani airport in the Democratic Republic of Congo, officials say.Up to 40 people have been found alive, but more than 50 others are known to have died, reports say.It is not known where the plane had flown from or the type of aircraft involved.The plane had tried to land in bad weather, an official from Congolese airline Hewa Bora told Reuters. "The pilot tried to land but apparently they didn't touch the runway," chief executive Stavros Papaioannou told the news agency. Hewa Bora is a private Congolese airline that runs scheduled flights from the capital, Kinshasa, to the central city of Kisangani and other destinations.The firm is on a European Union airline blacklist over safety concerns. According to Hewa Bora's website, the airline has eight planes in its fleet: five MD-82s, two Boeing 727s and one Boeing 727-266 ER.