Investigation Summary
The flight was the first leg of a multi-stop journey from Rio de Janeiro to Los Angeles. Upon reaching the Lima area, the crew reported being at 12,000 feet over Las Palmas, which was too high for the requested straight-in approach to Runway 33. Air Traffic Control suggested a 360-degree turn to lose altitude. The aircraft proceeded to fly a series of maneuvers, passing east of the airport, turning left over the field, and then heading south to intercept the ILS back course. During the final turn to intercept the 327-degree inbound track, the aircraft maintained its intercept heading for nearly three minutes longer than required. This delay placed the Boeing 707 in mountainous terrain east of the safe approach corridor. The investigation by CENIPA could not determine why the crew failed to turn onto the final approach course at the correct time, though secondary analysis suggests the pilot may have misinterpreted the instruments while flying the complex back course procedure, leading to the fatal three-mile eastward deviation.
Final Conclusions
The official investigation concluded the cause was a deviation, for reasons unknown, from the track prescribed for the instrument approach along the ILS back course of Lima-Callao Airport. The aircraft struck La Cruz Peak at an altitude of approximately 2,000 feet while on a heading of 333 degrees.
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Systems & Failure Modes
ILS Back Course
A non-precision approach using the reverse signal of a localizer; it requires the pilot to fly the reciprocal of the main approach heading.
Rolls-Royce Conway 508
The four bypass turbofan engines powering the Boeing 707-441.
Interesting Facts
- 01The aircraft was only two years old at the time of the accident.
- 02The flight carried two complete sets of crew, totaling 17 crew members.
- 03The crash site, La Cruz Peak, is also referred to in some records as Las Cruces hill.
- 04The aircraft struck the mountain about 8 miles east of the Morro Solar ILS back course track.
- 05At the time, it was the deadliest aviation accident in Peruvian history.
Safety Actions & Advisories
Back Course Approach Training
The accident highlighted the inherent risks and complexity of ILS back course procedures, which require pilots to fly the reciprocal of the localizer signal, often leading to 'reverse sensing' errors if not properly managed.