The FMA 20 El Boyero ("Shepherd") was a light utility aircraft produced in Argentina in the 1940s. It was a conventional high-wing strut-braced monoplane with fixed tailskid undercarriage with seating for two side-by-side in an enclosed cabin. Design work started in 1939 and two prototypes were built, the first flying in November 1940 and the second early the following year. Plans to put the aircraft into production were put on hold because of FMA's commitment to military production, and the design was sold to Sfreddo y Paolini, who in turn sold it to Petrolini Hermanos. Following the war, this firm received an order for 150 of the type from the Argentine government, and commenced deliveries in January 1949. The aircraft were distributed to Argentina's aeroclubs and to the military, which used it as a spotter aircraft. Petrolini experienced great difficulties sourcing sufficient materials to complete the order, and in 1951 ceased production, having completed 129 aircraft.