What happened
On 28 April, an international scheduled flight traveling from Buenos Aires, Argentina, to Santiago, Chile, was involved in an accident during its approach to Pudahuel Airport. The aircraft departed Ezeiza Airport at 2356 hours GMT, following an IFR flight plan via several waypoints including Juncal and Tabón.
During the descent phase, the aircraft received clearances to descend through various flight levels. After passing the Tabón NDB, the crew descended from FL 150 to FL 70. While approaching the ILS outer marker, the aircraft continued its descent at a rate of approximately 1,500 to 2,000 feet per minute. The aircraft passed below the minimum safety altitude of 2,829 feet without the crew noticing the deviation.
As the aircraft descended below the published minimum height of 1,749 feet, the radio altimeter warning light activated. Although the aircraft leveled off at that moment, the wheels contacted the ground in a field located 2 kilometers north of the ILS outer marker. The aircraft type sustained heavy damage during the impact, but there were no serious injuries among the passengers or crew.
Findings
An investigation into the accident identified several contributing factors related to crew performance and instrument monitoring. The primary cause was the excessive concentration of the crew on Flight Director indications, which led to the erroneous operation of the equipment during a direct ILS approach.
Because of this preoccupation, the crew failed to monitor critical instruments that would have indicated:
- The aircraft was descending below the minimum safety altitude
- The rate of descent was higher than normal for an ILS approach
- The longitudinal attitude of the aircraft was abnormal
- The aircraft's position had fallen below the ILS glide path