What happened
On a scheduled domestic service from Lima to Cuzco, Flight 501 departed Lima-Callao-Jorge Chavez International Airport at 07:40 local time. The flight was operating ten minutes behind its planned departure time. Following takeoff, the aircraft communicated with Lima radio at 07:57, providing an estimated arrival time for Ayacucho. This transmission served as the final contact from the crew before the aircraft disappeared.
Witnesses in the villages of San Pedro de Pilas and Tres Cruces observed the Boeing 727 (implied by weight/type context) flying at an unusually low altitude between the settlements of Tamard and San Pedro de Pilas. Observers noted that while they were accustomed to seeing aircraft at much higher altitudes, this flight was navigating through a gap in the terrain toward the mountain range. One witness reported seeing the airline's name on the fuselage, and another observed the aircraft performing a slight left turn to avoid the Huamantanga peak. There were no visible signs of fire or engine failure reported by those on the ground.
The wreckage was discovered on April 28 on the southeast slopes of Mount Talaula at an elevation of 12,600 feet. The accident resulted in 49 fatalities and no survivors. The crash site was located approximately 61 nautical miles from Lima-Callao Airport and significantly north of the intended flight path.
Findings
The investigation concluded that the primary cause was pilot error involving several critical mistakes. The pilot failed to follow the airline's established route procedures and incorrectly calculated the aircraft's climb performance relative to its takeoff weight. Specifically, the aircraft's weight prevented it from reaching the necessary altitude to clear the peaks of the Cordillera within the timeframe allowed by the chosen route.
Further contributing factors included:
- The pilot's incorrect estimation of the elevation of nearby mountain peaks.
- An unsafe decision to fly through a low-elevation gap between mountains that could not be cleared due to the aircraft's climb limitations.
- Potential impairment of the pilot's judgment due to fatigue and the stress of being assigned to a flight for which they were not originally rostered.
- The selection of a direct route, likely influenced by favorable weather conditions, which led to an unrecoverable flight path.