President Quett Masire of Botswana and an aide were slightly injured when an engine on the presidential jet exploded in flight, forcing an emergency landing in southeastern Angola. Masire and seven aides were flying to the Angolan capital of Luanda for a meeting of southern African heads of state when the right engine of the twin-engine, British-made executive jet exploded and fell off the aircraft, a presidential spokesman said. Metal fragments penetrated the jet's cabin, slightly injuring Masire and protocol chief Bashi Ikitseng, the spokesman said. The British pilot landed the damaged jet at Cuito Bie, 375 miles southeast of Luanda. Masire and Ikitseng were being treated in a Luanda hospital.