The Sud-Aviation GY-80 Horizon is a four-seat single engined low-wing aircraft built in France. The GY-80 Horizon was designed
by Yves Gardan during the 1950s. Piloted by Pierre Simon, the Gardan GY-80 Horizon prototype (c/n 01 F-WJDU) flew first on 21
July 1960. On 10 July 1062, Sud-Aviation acquired a license to build and market the four-seat all-metal light aircraft. The first
three of seven pre-production development models built by SOCATA (Société de Construction d'Avions de Tourisme et d'Affaires) under
licence for Sud Aviation were flown in early 1963. The type certificate for the GY-80-150 and the GY-80-160 was granted on 2 May 1963.
Deliveries of the Sud-Aviation GY-80 Horizon aircraft built by their full subsidiary SOCATA at Nantes and Rochefort started in 1963.
The four-seat cabin monoplane design used a low-mounted cantilever wing which incorporated four mechanically operated Fowler-type
trailing-edge flaps and two Frise-type ailerons. The tricycle undercarriage was partially retractable (a little more than half of
each wheel remains exposed in the retracted position). A simple structure was employed, comprising a light alloy-covered
welded steel-tube forward fuselage and a light alloy monocoque rear fuselage. The flap sections, and the fin and halves
of the slab-type tailplane were interchangeable. Three versions were initially offered, being respectively fitted
with a 150 hp Lycoming O-320-A four-cylinder air-cooled engine with fixed-pitch airscrew and a 160 hp O-320-B with fixed-
or variable-pitch airscrew. Later models had as standard powerplant a 160 hp Lycoming 0-320-D engine driving a fixed-pitch
two-blade propeller. Late in 1964, it was decided to supplant the 160 hp-engined model with a variant powered by a 180 hp Lycoming
0-360-A1A flat four piston engine. Flight testing of the more powerful model commenced during the autumn of that
year. The 180 hp engined Horizon featured a redesigned engine cowling and wheel fairings and a three-blade constant-speed
propeller was optional. However the vast majority of the GY-80 Horizon aircraft were delivered to civilian customers mainly in France,
ten GY-80-180 Horizon aircraft were used in Cambodia as military trainer, first with the Khmer Air Force where they replaced
the obsolete MS 733 Alcyons and later with the Royal Cambodian Air Force. In January 1968, the Australian Southern Aeronautics Pty Ltd
signed an agreement with Sud Aviation for the Australian franchise to distribute and manufacture the Sud Horizon. They would initially
assemble the GY-80 Horizon aircraft built in France and then gradually introduce Australian produced components until reaching 100%
Australian content. These plans were never realized and in August 1971 Southern Cross Aviation was wound up by a meeting of creditors
in Perth. When production of the Sud-Aviation GY-80 Horizon ended in 1969, a total of 267 GY-80 Horizon airframes were built.
Based on the GY-80 Hozizon design, Yves Gardan developed the GY100 Bagheera, a four-seat single engined low-wing aircraft. The SITAR GY 100 Bagheera
was equipped with a fixed gear and powered by a 135 hp Lycoming O-320 engine. Only two GY 100 Bagheera were built by SIPA, with the prototype flying on
20 December 1967. Although the type certification was granted in 1971, and SIPA would build the aircraft under subcontract of SITAR, the GY-100
Bagheera didn't enter production partly because the design arrived on the market at the moment of the oil crisis. An improved variant of the GY-80 Horizon
developed by SOCATA was the Super Horizon 200. Originally known as the Super Horizon 200, this four-seat civil light aircraft was later renamed ST 10 Provence,
before finally being named the ST-10 Diplomate. With the prototype flying on 7 November 1967, production started in 1970. When production ended in 1974, a total
of 55 ST 10 Diplomate aircraft were built.
On 29 June 1966, the Sud Aviation GY-80 Horizon s/n 152 was registered F-BNYC in France as a Gardan GY 80-160 D with Aèro Club de la Tour du Pin,
Aèrodrome de la Tour du Pin-Cessieu. When registered F-BNYC in 1966, the aircraft was fitted with a 160 hp Lycoming O-320 D2A engine. Since, the
1966-built Sud Aviation GY-80 Horizon was operated with a number of owners and was modified into a Sud Aviation GY-80-180 Horizon with a a 180 hp
Lycoming 0-360-A1A flat four piston engine. On 12 February 1996, Sud Aviation GY-80-180 Horizon F-BNYC was registered with G. Maij, Hoogwoud, the
Netherlands, and based at Lelystad Airport. On 4 June 2017, the Sud Aviation GY-80-180 Horizon F-BNYC was seen at Oostwold-Oldambt airfield, the
Netherlands, during the Oostwold Airshow 2017.