The aircraft involved was a nine-year-old Boeing 707-340C with serial number 20275 and serial 844. It was built in 1970 and on July 30 made its first flight. Ten days later, on 10 August, it was delivered to Pakistan International Airlines and was registered as AP-AWB. It was re-registered as AP-AWZ in 1972 after being leased for several months to another airline. The aircraft had 30,710 flight hours at the time of the crash.
Crash
The airliner operated as flight 740 from Jeddah to Karachi, during which it carried pilgrims returning from the Hajj. There were a total of 156 people on board, 11 crew members and 145 passengers. At 01:29, flight 740 departed from Jeddah and began to climb to the planned level of. The first warning of an emergency came at 01:47, 21 minutes after takeoff, the flight attendant informed the pilots that a fire had started in the back door. After reporting to the dispatcher about the situation on board and the beginning of the emergency descent from the echelon of, the crew received permission to descend to a height of. The pilot radioed a request to return to Jeddah because smoke was coming into the cabin and cockpit. At 02:03 the crew sent a distress signal. The Jeddah control tower heard the pilot shout "Mayday! Mayday!" before the radio went silent. After about a minute, the aircraft crashed into rocks and exploded. The crash site was at an altitude of. All 156 people on board died. The accident remains, to date, the third-deadliest plane crash on Saudi Arabian soil and the third-deadliest crash involving a Boeing 707.
Cause
The cause of the catastrophe was determined to be a fire that started in the rear of the cabin. The fire spread quickly, causing passengers to panic and run towards the front to escape the smoke. This disrupted the alignment of the aircraft which, in combination with the strong smoke, incapacitated the flight crew and lead to loss of control of the aircraft. The exact cause of the fire has not been determined. The most likely version is that there was a leak of gasoline or kerosene from one of the stoves, which the pilgrims took with them. Since the ascent pressure in the cabin becomes somewhat lower, a leaky gasket could lead to fuel leakage. There was a malfunction in the electrical circuits, but the rapid spread of fire in this case was difficult to explain due to the nature of the design of the aircraft’s electrical systems and protection devices. The chance of the crash being a terrorist attack was not confirmed, as there was no evidence that incendiary devices were used.
