JAKARTA, Indonesia—A small cargo plane crashed in a steep mountainous forest in Indonesia’s easternmost Papua province on Wednesday, killing all three people on board, officials said. Timika rescue agency chief George Leo Mercy Randang said rescuers had reached the crash site of the Rimbun Air plane and confirmed that all three crew members were dead. He said bad weather conditions and steep terrain were impeding the recovery of the victims. The Transportation Ministry said contact with the Twin Otter 300 plane was lost about 50 minutes after takeoff. It was heading to Intan Jaya district from Nabre district with construction materials on board. Randang said the weather conditions were sunny when the plane took off but were cloudy where it crashed. An aerial search located the crashed plane in Intan Jaya. At least 10 officers from the search agency, the Indonesian military, and national police trekked to the site. Indonesia, …