Flight 160 Accident: Descent Below Minimums During ILS Approach (CC-CAQ)

Flight Details and Route Clearance Flight 160 was a scheduled international service operating from Buenos Aires, Argentina, to Santiago, Chile. The aircraft departed Ezeiza Airport at 2356 GMT on an IFR flight plan for airways AJG 82 and UG-14. Its route took it over Junín, Villa Reynolds, El Pencal, Mendoza, Juncal, and Tabón, with an initial flight level of 310 (31,000 ft). ## Descent and Approach Sequence Before Juncal, Mendoza Control Centre cleared the aircraft to descend and maintain flight level 260 (26,000 ft). After passing Juncal, Santiago Control Centre cleared it to descend and maintain flight level 250 (25,000 ft), with instructions to pass the Tabón NDB at flight level 150. The crew received a Santiago weather report indicating 4/8 nimbostratus at 450 m and 8/8 altostratus at 2,400 m. At 0135 GMT, the aircraft passed over Juncal at flight level 260 and began descending toward flight level 150. It reported passing through flight level 180 (18,000 ft) and passed Tabón NDB at 0141 GMT, leaving flight level 150 for flight level 70 (7,000 ft). Santiago Centre had previously cleared the aircraft to flight level 70 at the Pudahuel Airport ILS outer marker. ## Descent Below Minimums The aircraft reported passing through flight level 70, and the control centre cleared it for an ILS approach, instructing a frequency change to 118.1 for Pudahuel Control Tower. It passed over Colina NDB at approximately 5,500 ft and intercepted the ILS glide slope at about 4,500 ft, one minute and 20 seconds after passing flight level 70. The aircraft continued descending at a rate of approximately 1,500 to 2,000 ft/min. It descended below the minimum height of 2,829 ft at the outer marker without the pilot or co-pilot noting the deviation, despite apparently correct indications from the Flight Director. The aircraft then passed below the published minimum height of 1,749 ft for Pudahuel Airport when the radio altimeter warning light illuminated. ## Impact and Outcome At the moment the warning light lit, the aircraft levelled off, but its wheels touched the ground. It landed in a field 2 km north of the ILS outer marker, suffering heavy damage. No serious injuries were reported among passengers or crew. The accident occurred at 0144 GMT on 28 April, corresponding to 2144 local time on 27 April.