Fairchild Swearingen Metroliner The Fairchild Swearingen Metroliner or the Fairchild Aerospace Metro is a 19 - seat , pressurised , twin turboprop airliner first produced by Swearingen Aircraft and later by Fairchild at a plant in San Antonio , Texas , United States . Design and development . The Metroliner was an evolution of the Swearingen Merlin turboprop - powered business aircraft . Ed Swearingen , a Texas fixed base operator ( FBO ) , started the developments that led to the Metro through gradual modifications to the Beechcraft Twin Bonanza and Queen Air business aircraft , aircraft he dubbed Excalibur . Then a new fuselage ( but with a similar nose ) and vertical fin were developed , married to salvaged and rebuilt ( wet ) Queen Air wings and horizontal tails , and Twin Bonanza landing gear ; this became the SA26 Merlin , more - or - less a pressurized Excalibur . Through successive models ( the SA26 - T Merlin IIA and SA26 - AT Merlin IIB ) the engines were changed to Pratt & Whitney Canada PT6 and then Garrett TPE331 turboprops . These were marketed as business aircraft seating eight to 10 passengers . An all - new aircraft was built and called the SA226 - T Merlin III with new nose , wings , landing gear , cruciform horizontal tail and inverted inlet Garrett engines . Ultimately a stretch of the Merlin III was designed , sized to seat 22 passengers and called the SA226 - TC 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 . The standard engines offered were two TPE331 - 3UW turboprops driving three - bladed propellers . A corporate version called the SA226 - AT Merlin IVA was also marketed and initially sales of this version were roughly double that of the Metro . Prototype construction of the Metro began in 1968 and first flight was on August 26 , 1969 . Swearingen Aircraft encountered financial difficulties at this stage , and late in 1971 Fairchild ( which was marketing the Metro and building its wings and engine nacelles ) , bought 90 % of Swearingen and the company was renamed Swearingen Aviation Corporation . It was at this point that the previously cash - strapped company was able to put the Metro into production . In 1974 , the original Metro models were replaced by the SA226 - TC Metro II after about 20 Metros and about 30 Merlin IVAs had been built . Among the changes made were larger , squared - oval windows and optional provision for a small Rocket - Assisted Take Off ( RATO ) rocket in the tail cone , this being offered to improve takeoff performance out of " hot & high " airfields in the event of an engine failure . The Metro and Metro II were limited to a maximum weight of 12 , 500 pounds ( 5 , 670 kg ) in the USA and countries using imperial units , and 5 , 700 kg in countries using SI units . When this restriction was lifted the Metro II was re - certified as the Metro IIA in 1980 with a maximum weight of 13 , 100 pounds ( 5 , 941 kg ) and the Metro II ' s TPE331 - 3 engines replaced by - 10 engines of increased power . The SA227 - AC 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 . Externally , improvements incorporated into the Metro III were a 10 ft ( 3 . 05 m ) increase in wing span , four - bladed props , redesigned " quick - access " engine cowlings and numerous drag - reducing airframe modifications , including landing gear doors that close after the gear is extended . Once again a corporate version was offered as the Merlin IVC ( the model name was chosen to align with the contemporaneous short - fuselage Merlin IIIC ) . A version with strengthened floors and the high gross weight option was offered as a cargo aircraft known as the Expediter . Both the Expediter and the Merlin IVC were designated the SA227 - AT . Finally , due to reliability problems with Garrett engines in the second half of the 1980s , the Metro IIIA was offered with two Pratt & Whitney Canada PT6 A - 45R turboprops in place of the Garrett units ; however none were actually delivered . A special model was the SA227 - BC Metro III built for Mexican airline AeroLitoral , which took delivery of 15 of the 18 of this model that were produced . Improvements beyond the Metro III provided better systems , more power and a further increase in takeoff weight . This design effort resulted in the SA227 CC ( for Commuter Category ) and SA227 - DC models , initially called the Metro IV then renamed Metro 23 , so named as they were designed for certification under FAR Part 23 ( Amendment 34 ) standards . A Metro 23 EF with an external pod under the lower fuselage for greater baggage capacity was also offered as well as an Expediter 23 and Merlin 23 . The SA227 - CC was an interim model with TPE331 - 11U engines and only a handful were built . Further development . In the 1960s Swearingen Aircraft developed a prototype SA - 28T eight - seat jet aircraft with a flapless delta wing . It shared the tail and cockpit with the Merlin / Metro . The two engines were to be Garrett TFE731 turbofans then in development ; they were originally to be mounted on the aft fuselage , however during the course of design work their location was moved to under the high - mounted wing . Early flights were to be undertaken with General Electric CJ610 engines fitted . Development continued after Fairchild acquired the company , but the project was shut down nine weeks from first flight . It was later cut up as scrap and the fuselage used as a Metro display at trade shows . 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 longer fuselage with a taller " stand - up " cabin providing 69 in ( 180 cm ) of interior height for passengers ; a redesigned , longer wing ; engines moved further out on the wing from the fuselage ; a " T - tail " and various system improvements . A Merlin V corporate version of the Metro V was also planned . The Metro V was to be fitted with the same engines as the Metro 23 and the Metro VI was to be fitted with more powerful TPE331 - 14 engines . The Metro VI was shelved within months of being announced due to a lack of customer interest , but Fairchild did not proceed with the Metro V either . One version that did see the light of day was the Metro 25 , which featured an increased passenger capacity of 25 at the expense of the baggage space found in earlier models ; the deletion of the left rear cargo door and the addition of a passenger door on the right - hand rear fuselage ; and a belly pod for baggage . A Metro III was converted as a Metro 25 demonstrator , it flew in this configuration in October 1989 . Also mooted but not built was the Metro 25J , which would have been another jet - powered aircraft with TFE731s in over - wing pods . The type certificates for Metro and Merlin aircraft are currently held by M7 Aerospace . Operational history . Two of the original Metro model 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 Commuter Airlines in January 1973 , followed shortly after by Air Wisconsin . At least one Metro IIA flies in Canada with Perimeter Aviation . Two SA227 - CCs are today registered with Canadian operator Bearskin Lake Air Service Ltd . , while another two are operating in New Zealand . A fifth also flew with Bearskin Airlines but was destroyed in a mid - air collision in 1995 . In service with Perimeter Aviation in Canada , this long - term operator of the Metro II made a number of modifications to suit its use in northern and remote Canadian sites where rudimentary gravel " strips " were common . Some of the many innovative changes to the design of the Metro allowed the aircraft to fly more efficiently as well as cutting down on the " noise factor " that was attributed to the early models . The airline installed Garrett engines with quieter and more efficient four - bladed Hartzell propellers . Their Metros are also all equipped with modern avionics suites including certified AlliedSignal KLN 90B GPS . Many of the improvements resulting in the Metro 23 came about during work to produce the military C - 26B model for the United States Air Force . A Metro III aircraft was modified for the Colombian Air Force for counternarcotics reconnaissance purposes . The Colombian National Police also operates several Metro 23 aircraft for counternarcotics reconnaissance purposes . In addition , the Peruvian Navy operates a Metro 23 and the Trinidad and Tobago Coast Guard operates a Metro III , both similarly configured . A " Regional Security System " Metro III with a large belly radome has been seen in the Caribbean . In civilian service the type has proved to be popular , with sales in the 19 - seat airliner market rivalled only by the Beechcraft 1900 . It is especially popular in Australia . Since the first example ( a Merlin IVA ) arrived in 1975 , almost 20 % of the fleet has operated in that country . As of December 2008 , 61 Metros and Expediters are registered in Australia , more than all of its market rivals combined . Metro production ended in 1998 , however by this time Regional Jet s were in vogue and turboprop types were out of favour with airlines , and several airframes remained unsold at the factory . The final aircraft , Metro 23 c / n DC - 904B , was not delivered ( to air charter company National Jet Aviation Services of Zelienople , Pennsylvania ) until 2001 . A total of 703 Metro , Expediter , Merlin IV series and C - 26 series aircraft were built . In addition , 158 other SA226 and SA227 series aircraft were built as short - fuselage Merlin IIIs , IIIAs and IIIBs . Operators . Civil operators . As of July 2012 a total of 342 Fairchild Metro / Merlin aircraft ( all variants ) remained in airline service . Major operators include : Over 60 other airlines also operate smaller numbers of the type .