A regional airliner crashed in a northeastern city in Brazil, killing all 16 people on board, the country's air force said Wednesday. The crew of the twin-turboprop aircraft belonging to Noar Airlines reported problems shortly after taking off from the city of Recife en route to the city of Natal. The air force did not indicate what the problems were or what caused the crash but said it is investigating. Weather did not appear to be a factor. About five minutes after taking off, the pilot attempted to make an emergency landing in a vacant lot near a beach outside the city center, near several apartment buildings. But witnesses said the airplane crashed and burst into flames shortly afterward. Recife Fire Chief Valdyr Oliveira told state radio that the fire was controlled quickly and that investigators are working at the scene for clues as to why the airplane crashed. "The pilot was able to land, but the impact caused an explosion," he said.