LAPA Flight 3142
LAPA Flight 3142 was a scheduled Buenos Aires–Córdoba flight operated by the Argentine airline Líneas Aéreas Privadas Argentinas. On 31 August 1999, the Boeing 737-204C operating the flight crashed while attempting to take off from Aeroparque Jorge Newbery International Airport in Buenos Aires, Argentina.
The crash resulted in 65 fatalities – 63 occupants of the aircraft and 2 people on the ground – as well as injuries, some serious, to at least 34 people. As of 2025, it remains the second deadliest aviation accident to occur in Argentina, behind Aerolíneas Argentinas Flight 644, 38 years prior.
Background
Aircraft
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. 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.
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 old.
Crew
In command was Captain Gustavo Weigel, aged 45, who had logged 6,500 hours of flying experience, 1700 of which were logged on the Boeing 737. His co-pilot was Luis Etcheverry, aged 31, who had logged about 4,000 hours of flying experience, 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".
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.
Accident
As the aircraft started its takeoff run, the take-off warning system 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 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, under negligent supervision of the Argentine Air Force, 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.
Analysis
The JIAAC review of the flight reads:The report details:
After impact against the embankment, but before catching fire, a flight attendant attempted to operate a fire extinguisher, but did not succeed because the cabin had already reached high temperatures. She also unsuccessfully tried to open the rear right door that was jammed – probably due to deformation. Finally, another flight attendant succeeded in opening the rear left door allowing several passengers to be evacuated before the fire spread. The right side of the fuselage showed an opening, through which a few passengers escaped.
Regarding the doors, preliminary versions of the report added that "the front left slide L1, of grey colour, was found deployed but unpressurised", which means a much greater than normal effort was needed to open the door. The early reports also considered that the absence of a food or drinks trolley in the rear galley of the aircraft helped, since walking distance to the exit was notably reduced.
Fire units from the airport, as well as the Federal Police, and the Naval Prefecture fought the fire. The evacuation operation was directed by the city's Medical Emergency Attention Service, which used 15 ambulances of their own as well as some from private hospitals. Based on the severity of their injuries, the casualties were taken to different treatment centres.
JIAAC investigation
The Junta de Investigaciones de Accidentes de Aviación Civil investigation report was only one of the documents taken into account in the judicial investigation, though it was criticized for focusing solely on blaming the pilots directly.During the three days after the accident, the United States National Transportation Safety Board sent a team to assist the JIAAC in their investigation. This team consisted of an NTSB representative and technicians from Boeing, Pratt & Whitney, and the US Federal Aviation Administration. While in Argentina, these investigators worked with JIAAC personnel, forming teams according to their areas of expertise.
The data from the flight data recorder and the cockpit voice recorder was read at the NTSB headquarters in Washington. With this information, a computerized animation of the failed take-off attempt was constructed.
Another aspect that was studied and analyzed was the adherence to the maintenance plan in the available technical documentation. The analysis led investigators to believe that the aircraft, its components and its engines complied with the requirements set out in the maintenance plan and the approved operational specifications of the Dirección Nacional de Aeronavegabilidad.
To complete the detailed investigation, the JIAAC technicians reassembled the main components of the aircraft in a hangar in the Aeroparque. They also cleaned, identified and analyzed the boards, actuators, electronic equipment, the cockpit pedestal, and other flight controls that were recovered from the accident site, and dismantled the engines of the plane as much as possible given the state of destruction they faced. The technicians inspected the hydraulic system on the thrust reversers of both engines and the braking system of the landing gear, all of which were found to be in sufficient working order.
Engines & thrust reversers
The investigation concluded that the engines almost certainly functioned until the final impact, though their behaviour at that particular moment could not be precisely determined. Nevertheless, from the reading of the FDR it was observed that both engines had equal thrust and were set to provide thrust for take-off before power was reduced and the thrust reversers were applied. In order to determine if there was a bird strike, the National Institute for the Investigation of Natural Sciences performed a study with negative results.The thrust reversers – which are located behind the engine and direct the exhaust forward to slow the aircraft down quickly after landing – were found seriously damaged, but the hydraulic mechanism of the left engine was set for reverse thrust while the right one was set for forward thrust. The investigation was unable to determine if the thrust reversers were intentionally activated and later deactivated.
Control surfaces
It was important for the investigation to establish the position of the mechanical activators on the flaps, since their lack of deployment was a fundamental cause of the accident. A special investigation was carried out to establish what had happened with the flaps. The extended flaps alter the aerodynamic characteristics of the aircraft, giving the aircraft lift to get off the ground at a lower speed over a shorter distance than would be possible without flaps. This is why in practice there are no runways that allow the take-off of medium- to large- size aircraft without flaps.The main finding within the remains of the plane was that all of the examined flaps' worm gear operators were in the unwound position, indicating that the flaps were not deployed. This finding was supported by the flap command in the cockpit that was also in the no-flaps position, the readings at the FDR indicating the flaps were retracted, and the extinguished flap lights indicating that they were not activated.
Other analyses
The alarm sound recorded by the CVR indicated that there was a problem with the departure configurations. The recording showed that at the time of departure the flaps were not in the correct position for lift-off.A study was performed on the electrical circuitry to determine the position of the electrical breakers on the take-off warning system. Also, a study was performed on the slat indicator lights' filaments.
The indicator lights were found to be off, the only fire alarm was off, and the main warning indicators were found on. The latter could be activated by any one of a long list of possible faults resulting in the destruction of the aircraft.