On May 9, 1976, the Boeing 747-131 freighter operating the flight crashed during its approach to Madrid, killing all 17 people on board.

[2][3][4]: 3 The aircraft's last maintenance check was performed by the Imperial Iranian Air Force on May 4, 1976, after which it flew for 16 hours.

[4]: 3 At 14:15, Flight 48 contacted the Madrid Air Route Traffic Control Center and reported that the estimated landing time would be 14:40.

At 14:33, the crew contacted Madrid approach and reported more bad weather ahead, subsequently requesting to deviate away from it.

The approach controller reported that he had established radar contact, and then asked the crew to confirm their instructions.

[4]: 2–3 At the same time, south of the town of Valdemoro, locals noticed the aircraft flying at around 6,000 feet (1,800 m) on a 220° heading.

The aircraft dove rapidly and it crashed onto a farm at a height 3,000 feet (910 meters) above sea level at 14:35 (15:35 local time), 54 seconds after the moment of the lightning strike.

[4]: 3–5 [5] The Imperial Iranian Air Force and the United States National Transportation Safety Board investigated the accident.

[4]: 1 It was established that a bolt of lightning struck the fuselage near the cockpit and exited the left wing's static discharger located at the wingtip.

As the flight was passing through an area of turbulence at high speed, the wing experienced major mechanical stress.