Fairchild Swearingen Metroliner

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Metroliner
Perimeter Aviation Metro II coming in to a northern Manitoba airport c.2006
Type	regional airliner
Manufacturer	Fairchild
Maiden flight	26 August 1969
Status	Currently in use
Primary users	Ameriflight Perimeter Aviation Key Lime Air Jetcraft Aviation
Produced	1968-2001
Number built	600
Developed from	Swearingen Merlin

The Fairchild Swearingen Metroliner or the Fairchild Aerospace Metro is a 19-seat, pressurised, twin turboprop airliner first produced by Swearingen and later by Fairchild.

Contents 1 Design and development 2 Operational service 3 Variants 3.1 Civilian 3.2 Military 4 Operators 4.1 Civil operators 4.2 Military Operators 5 Specifications 5.1 Metro III 5.2 C-26A 6 References 7 Related content

[edit] Design and development

The Metroliner was produced as development of the Swearingen Merlin turboprop-powered business aircraft. Ed Swearingen started the developments that led to the Metro through gradual modifications to the Beechcraft Queen Air business aircraft, aircraft he dubbed Excalibur.

Then a new fuselage and vertical fin were developed, married to salvaged and rebuilt (wet) Beechcraft wings, horizontal tail, and landing gear and this became the Merlin, powered by PT 6 turboprop engines. These were marketed as business aircraft seating eight to ten passengers. Through successive models (Merlin I, II,) the engines were changed to Garret fixed shaft.

An all new aircraft was built and called the Merlin III with new wings, landing gear, cruciform horizontal tail and inverted inlet Garret engines. Ultimately what was designed was a stretch of the Merlin III, sized to seat 22 passengers and called the Metro. Because FAA regulations limited an airliner to no more than 19 seats if no flight attendant was to be carried, the aircraft was optimized for that number of passengers. A corporate version with adjusted fuselage length, called the Merlin IV was also marketed.

In extreme secrecy, Swearingen Aircraft developed a prototype SA 29 T Jet aircraft with modified airfoil, Friese differential ailerons, inboard swinging landing gear and other refinements. It shared the tail and cockpit with the Merlin/Metro. Fuselage had aft mounted engines to be the Garret 731 Turbofans that were in development. First flights were to be CJ 610 GE powered. When Fairchild acquired the company, this project was shut down 9 weeks from first flight. It was later cut up as scrap and the fuselage used as a Metro display at trade shows.

Prototype construction of the Metro began in 1968 and first flight was on 26 August 1969.

[edit] Operational service

Two of this original model, also identified as the SA-226TC, were delivered in 1972 to Societe Miniere de Bakwanga (MIBA) in Kinshasa, Zaire, the first customer to put the Metro into service. The first airline to put them into service was Air Wisconsin.

Late in 1971, Swearingen was acquired by Fairchild, and the plant in San Antonio, Texas where the Metro was built became part of Fairchild Aircraft Corporation.

In 1974, the original Metro I model was replaced with the Metro II. Among the changes made were larger, square windows and provision for a small rocket motor in the tail cone, this being offered to improve takeoff performance out of "hot & high" airfields. The aircraft is the only turboprop to have a trimmable horizontal stabilizer (THS) usually used only on jet aircraft.

The Metro I and II were limited, again by FAA regulation, to a maximum weight of 12,500 pounds (5,670 kg). When this restriction was lifted the Metro II was recertified as the Metro IIA in 1980 at a maximum weight of 13,100 pounds (5,941 kg). The standard engines offered were two Garrett TPE331 turboprops driving three-bladed propellers.

The Metro III was next, also initially certified in 1980 at up to 14,000 pounds (6,350 kg) this increasing to 14,500 pounds (6,577 kg) as engines and structures were upgraded. An option to go as high as 16,000 pounds (7,257 kg) was offered. Other improvements incorporated into the Metro III were a 10 ft (3.05 m) increase in wing span, four-bladed props, and numerous drag-reducing airframe modifications. A version with strengthened floors, aft loading doors, and the high gross weight option was offered as a cargo-only version known as the Expeditor. Finally, the Metro IIIA was offered with two Pratt & Whitney Canada PT6A-45R turboprops in place of the Garrett units.

Improvements beyond the Metro III provided better systems, more power and a further increase in takeoff weight. This work resulted in the Metro 23, so named as it was designed for certification under FAR Part 23 (Amendment 34) standards. Many of these improvements also came about during work to produce the military C-26 model. A Metro 23 EF with a bulged lower fuselage for greater baggage capacity was also offered as well as an Expeditor 23.

Although Fairchild studied a version with a "stand-up" cabin (as in the Beechcraft 1900D), this was not built. At the 1987 Paris Air Show, Fairchild released details of proposed developments of the Metro designated the Metro V and Metro VI. These versions would have featured a Metro III fuselage with a redesigned, longer wing, more powerful Garrett engines moved further out on the wing from the fuselage, a "T-tail" and various system improvements. Difference in engine power was what determined if a model was a Metro V or Metro VI, the Metro VI being the more powerful aircraft.

The last Metro (a Metro 23 model) was produced in 2001. Over 600 Metros were built.

[edit] Variants

[edit] Civilian

• Metro I
• Metro II
• Metro III
• Merlin IV
• Metro 23
• Metro 23EF

[edit] Military

C-26 Metroliner is the designation in the service of the United States military.

• C-26A - military version of the Metro III (Model SA227-AC)
• C-26B - military version of the Metro 23 (Model SA227-DC)
• RC-26B - C-26B modified with electronic surveillance equipment for drug interdiction missions (USAF operates 11)^[1]
• UC-26C is the military version of the Merlin IV-C.
• Tp88 - Metro III (one aircraft) delivered to the Swedish Air Force for use as a VIP transport.

[edit] Operators

[edit] Civil operators

In August 2006 a total of 377 Fairchild Metro/Merlin aircraft (all variants) remain in airline service. Major operators include: Jetcraft Aviation (10), Macair Airlines (9),Peninsula Airways (6), Pel-Air (10), Air Cerberus (7), Ameriflight (44), Bearskin Airlines (8), Berry Aviation (10), Big Sky Airlines (7), IBC Airways (10), Key Lime Air (16), Merlin Airways (12), Perimeter Aviation (21) and Superior Aviation (8). Some 92 other airlines also operate smaller numbers of the type.^[2]

[edit] Military Operators

• Argentina, El Salvador, Mexico, Sweden, Thailand, Trinidad and Tobago, United States (US Navy, US Air Force, US Army)

[edit] Specifications

[edit] Metro III

• Crew: 2 (pilot + first officer)
  • 1 pilot in cargo only configuration
• Accommodation: 19
• Max speed: 311 knots (576 km/h) (246 knots indicated)
• Cruising speed: 278 knots (515 km/h)
• Range:
  • Maximum takeoff weight of 14,500 lb (6,577 kg): 575 nm (1,065 km)
  • Maximum takeoff weight of 16,000 lb (7,257 kg): 1,150 nm (2,131 km)
• Wingspan: 57 ft (17.37 m)
• Wing area: 309 ft² (28.71 m²)
• Length: 59 ft, 4 in (18.09 m)
• Height: 16 ft, 8 in (5.08 m)
• Cargo Volume: 143.5 ft³ (4.06 m³)
• Maximum Take-Off Weight: 14,500 lbs (6,577 kg) or 16,000 lbs (7,257 kg), depending on model
• Powerplant: 2 x 745.5 kW/1,000 shp (dry), 820 kW/1,100 shp (wet) (flat rated) Garrett TPE331-11U-612G turbprops with continuous alcohol-water injection equipped with four-bladed McCauley C652 propellers.

[edit] C-26A

General characteristics

• Crew: 2
• Capacity: 22/14 passengers
• Length: 42 ft 2 in (12.85 m)
• Wingspan: 46 ft 3 in (14.01 m)
• Height: 16.83 ft (5.13 m)
• Wing area: ft² (m²)
• Empty weight: lb (kg)
• Max takeoff weight: 14,000 lb (6,400 kg)
• Fuel: 625 gal (2,370 L)
• Powerplant: 2× Allied Signal Garrett TPE-331-IIUG-601G turboprop, 1,100 hp (820 kW) each

Performance

• Maximum speed: 248 knots (285 mph, 460 km/h)
• Range: 2,025 nm (2,331 mi, 3,750 km)
• Service ceiling: 31,000 ft (9,500 m)
• Power/mass: 0.08 hp/lb (130 W/kg)

[edit] References

[edit] Related content

Designation sequence

• C-23 - C-24 - VC-25 - C-26 - C-27 - C-28 - C-29

Related lists

• List of military aircraft of the United States