Accident
While cruising on a flight from Asunción to Buenos Aires, the airplane, christened 'Mariano Moreno' and registered LV-ADS, experienced a major issue on engine number three. Shortly after, the airplane disintegrated in the air, dove into the ground, and crashed in an open field located 12 kilometers northeast of Salto. The aircraft was totally destroyed and debris were scattered over more than five kilometers. All 31 occupants were killed.
Investigation and Probable Cause
The official investigation determined the probable cause. The immediate cause was overspeeding of the No.3 propeller caused by irregular operation of the propeller governor, detachment of that propeller, and impact with the propeller of No.4 engine, followed by disintegration of the aircraft. The remote cause was insufficiently strict observance of engine maintenance conditions. While Pratt and Whitney Service Bulletins Nos. 1666 and 1680, dated 5 November 1957 and 15 May 1958 respectively, were not mandatory, the company should have taken account of the special circumstances in the history of No.3 engine, which resulted in the destruction of LV-ADS.