Today in 1969 the Fairchild Swearingen Metroliner made its first flight. Due to several takeovers, the aircraft was/os also known as the Swearingen Metro and also as the Fairchild Aerospace Metro.
This 19 seat, twin-turboprop with a pressurised cabin would be built in great numbers from 1968 till 2001, with more than 600 of these aircraft built in different versions, both for civil and (para)military use.
The aircraft is a development of the Swearingen Merlin, a turboprop business aircraft. However, parts and systems of other aircraft were also used in the design. The (donor) aircraft used were the Beechcraft Twin Bonanza and the Beechcraft Queen Air. The development of the Metroliner started in 1968, it had a new fuselage with a nose section similar to the Swearingen Merlin. A new vertical stabiliser was designed. This new fuselage was joined to salvaged and rebuilt wings of a Beechcraft Queen Air and the landing gear of a Beechcraft Twin Bonanza. This aircraft was the SA26 Merlin. Through further modifications the company develop the aircraft into an SA26-T Merlin IIA (with P&W Canada PT6 turboprop engines) and an SA-26AT Merlin IIB (with Garrett TPE331 turboprop engines). These aircraft were offered as business aircraft with a capacity for 8 to 10 passengers. Following the designs mentioned above, an all-new design came out of the design department. This aircraft was called the SA226-T Merlin III. Compared to the previous models the design featured a new nose section, new wing and landing gear, modernised tail section and Garret Engines. Like its ancestors also the Merlin III design changed, with a stretched fuselage the new version was called the SA226-TC Metro, capable of accommodating 22 passengers. At this time FAA regulation limited an aircraft to 19 seats if it was to be operated without a cabin attendant. This regulation led to a reconfiguration of the SA226-TC Metro cabin to accommodate a maximum of 19 passengers.
The propellers were driven by
Garret TPE331-3UW engines, which were the standard engines offered An SA226-AT Merlin IVA was also offered as a business aircraft version of the SA226-TC Metro. Several other modifications were incorporated over the years in the different models. Larger windows and the (optional) provision for the installation of Rocket-Assisted Take Off (RATO) rockets, this for improved performance out of hot and high airports in case of an engine failure on takeoff.
Garret TP331 engine on a Metro III
Eight versions of the aircraft would be built, with the military identifying the aircraft as the C-26.
Specifications for a Metro III
Crew: 2 (pilot & first officer), 1 in cargo-only configuration
Capacity: 19 passengers
Length: 59 ft 4 in (18.08 m)
Wingspan: 57 ft 0 in (17.37 m)
Height: 16 ft 8 in (5.08 m)
Wing area: 310 sq ft (29 m2)
Empty weight: 8,737 lb (3,963 kg)
Max takeoff weight: 14,500–16,000 lb (6,577–7,257 kg)
Powerplant: 2 × Garrett AiResearch TPE-331 turboprop engines, - 1,000 shp (750 kW) each - 1,100 shp (820 kW) with alcohol-water injection
Propellers: 4-bladed McCauley 4HFR34C652 or Dowty Rotol R.321/4-82-F/8
Maximum speed: 311 kn (358 mph, 576 km/h)
Cruise speed: 278 kn (320 mph, 515 km/h)
Range: 594 nmi (684 mi, 1,100 km) 
Service ceiling: 25,000 ft (7,600 m)