It was registered as N54627 during a certification test but re-registered as EC-CBN when it was delivered to Iberia Airlines in August 1973.

[3][4] The cockpit crew consisted of Captain Jesus Calderón Gaztelu (age 53), First Officer Alfredo Perez Vega (54), Flight Engineer Celedonio Martin Santos (42), and Radio Operator/Navigator Candido Garcia Bueno (51).

According to the aircraft's flight data recorder, the descent rate was increasing too rapidly during the approach, the result of a wind shear encounter.

The investigation found that the captain and the first officer failed to recognize the rate change until the aircraft collided with the ALS piers.

The captain's ability to detect and arrest the increased rate of descent was adversely affected by a lack of information as to the existence of the wind shear and the marginal visual cues available.

The minimal DC-10 wheel clearance above the approach lights and the runway threshold afforded by the ILS glide slope made the response time critical and, under the circumstances, produced a situation wherein a pilot's ability to make a safe landing was greatly diminished.

This meant that the passengers in the back had to climb out of the section through the roof that had broken and jump off onto the ground, causing even more injuries.