PIA flight 740, a Boeing 707-300, crashed near Taif, Saudi Arabia, following an in-flight fire, killing all 156 occupants. Flight PK740 departed Jeddah at 01:29 for a flight to Karachi. The aircraft was climbing to FL370 when, at 01:47, a stewardess reported a fire near the aft cabin passenger door. The crew started a descent from FL300 and were cleared to descend to 4000 feet. Following a mayday call at 02:03 nothing more was heard from the flight. The aircraft crashed in a level rocky area at an elevation of 3000 feet and burst into flames. PROBABLE CAUSE: “An in-flight fire in the cabin area which, through its intensity and rapid extension, resulted in panic among the passengers and smoke in the cockpit, eventually incapacitating the flight crew. The cause of the cabin fire was not determined.” It was considered that the origin of the cabin fire could have been a leaking gasoline or kerosene stove, carried aboard by Haj pilgrim passengers. Pressure differential could have caused a poorly sealed gasket to leak fuel. A second possibility is an electrical fire, but the rapid extension of the fire was considered difficult to explain because of the electrical circuit protection devices of the Boeing 707. Sabotage was considered as another possibility, but no evidence of use of an incendiary device was found.