About LAPA flight 3142:

The aircraft was Boeing 737-204C, registered as LV-WRZ with serial number 20389 and line number 251. It was also powered by two JT8D-9A engines.[1] It first flew on 14 April 1970, and was delivered to Britannia Airways on 17 April of that year as G-AXNB.

Almost 20 years later, on 1 February 1990, the aircraft was sold to the French airline TAT European Airlines, and registered as F-GGPB.[citation needed]

Finally, the aircraft was delivered to LAPA on 21 December 1996. At the time it crashed, it had accumulated 64,564 hours of flight time and 38,680 take-off/landing cycles. The aircraft was 29 years and 139 days old.[4]

In command was Captain Gustavo Weigel, aged 45, who had logged 6,500 hours of flying exeprience, 1700 of which were logged on the Boeing 737. His co-pilot was Luis Etcheverry, aged 31, who had logged about 4,000 of flying experiece, including 600 on the Boeing 737. Both pilots died in the accident.

With regard to the two pilots, the JIAAC report said that "the records of their flight and simulator training showed repeated negative flying characteristics, and if they had been able to move away from these characteristics in the face of difficulties, their poor attitude manifested itself once again in relaxed attitudes such as that seen in the cockpit of flight 3142".[5]

Even though the report stated that "the pilots had fulfilled technical and psychological requirements", and that "their experience, both in general flight, and with this kind of aircraft was suitable for the job they were performing", a lawsuit later determined that Weigel was not fit to fly, since his license had expired.

Even though these personal issues surrounding the pilots had a very significant influence on the accident, the legal investigation performed in the following years centered on proving that the pilots were not entirely to blame, but that the lack of controls by the Air Force and LAPA's organizational culture also played a role in the events leading to the crash.
As the aircraft started its takeoff run, the take-off warning system (TOWS) sounded an alarm indicating that the aircraft was not correctly configured for takeoff. The crew ignored the warning and continued not realising that the flaps were not at the required takeoff position and were instead fully retracted. The jet overshot the runway, breaking through the airport's perimeter fence, crossed a road, hitting an automobile in the process, and finally collided with road construction machinery and a highway median. Fuel spilling over the hot engines and gas leaking from a damaged gas regulation station resulted in a fire that destroyed the aircraft.

The Junta de Investigaciones de Accidentes de Aviación Civil (JIAAC) determined that the pilots failed to configure the aircraft correctly for takeoff. The penal prosecution focused on proving that the company's policies and organization, lacking the Argentine Air Force's controls, were the main factors that led to the accident. For instance, it was mentioned that a pilot was allowed to fly without a license by the company. Because of these perceived flaws, some of LAPA's directors and the Air Force staff responsible for monitoring the airline were taken to jury trial.

Investigation:

According to the investigative commission, the immediate cause of the accident was "that the flight crew of LAPA flight 3142 forgot to extend the wing flaps to initiate take-off, and ignored the alarm that advised them of the error in configuration for take-off."