What happened
On the scheduled flight from Rio de Janeiro-Galeão Airport to Los Angeles via several intermediate stops, a Boeing 707-441 operated by Varig was conducting its descent toward Lima-Callao Airport. At approximately 08:09 UTC, the aircraft reported being at 36,000 feet and requested permission to begin its descent. During this period, Air Traffic Control in Lima notified the crew of a DC-6 operating at a lower altitude in the same vicinity.
Following the passage of Pisco, the flight crew initiated a descent toward runway 33. By 08:19 UTC, the aircraft had reached 26,000 feet, and by 08:24 UTC, it was at 15,000 feet. Because the aircraft's altitude was too high for a direct straight-in approach, controllers instructed the crew to perform a 360-degree turn over Las Palmas. The aircraft proceeded with its maneuvers, passing east of Lima Airport and then over Lima-Callao Airport before turning south to begin the outbound procedure for the ILS back course.
While attempting to intercept the ILS back course at a heading of 327 degrees, the aircraft maintained a standard intercept course for nearly three minutes before initiating its turn toward the north. During this maneuver, the Boeing 707-441 struck the side of La Cruz Peak, approximately 8 miles east of the prescribed approach track. The impact resulted in 97 fatalities, representing all 80 passengers and 17 crew members on board.
Findings
The investigation determined that the aircraft had deviated from the established flight path required for the instrument approach along the Lima-Callao Airport ILS back course.