PORT-AU-PRINCE, Haiti (AP) - A commuter passenger plane exploded and crashed after take off Sunday from Haiti's northern city of Cap-Haitien, killing all 21 aboard, news reports said. Five minutes after it took off Sunday afternoon, witnesses saw smoke billowing from the twin-propeller plane which sent distress signals to the Cap-Haitien control tower, private Radio Maxima reported. There was an explosion and crash, witnesses told the radio station's director Jean-Robert Lalane, who spoke to The Associated Press AP by telephone from the scene. It was unclear whether the explosion came before or after the crash, he said. Lalane said...