A BOEING 727 passenger jet, grounded at Luanda airport a year ago, has disappeared after a mysterious unauthorised take-off, Angola state radio reported today. The plane, chartered by the Angolan airline Airangol, was grounded after being banned from overflying Angolan territory on account of a series of irregularities, said Angola civil aviation director Helder Preza. A witness to the plane's departure on Sunday, airport employee Luis Lopes, said he saw a white man start the empty plane and then take off after a few dangerous land manoeuvres. Airport chief Celso Rosa said there was some evidence to believe the Boeing...