Fairchild Metroliner SA227-DC Metro 23

The improvements that followed the Metro III — better systems, more power and another increase in maximum take-off weight — led to two models: the SA227-CC (the letters stand for Commuter Category) and the SA227-DC. They were initially called the Metro IV but were renamed Metro 23 because they were designed for certification under Part 23 of the Federal Aviation Regulations (FAR), Amendment 34. Few aircraft take their name from the number of the rule that certifies them. According to the type's history, many of those improvements came out of the work to produce the C-26B, the military version built for the United States Air Force.

The two versions differed in their engines. The SA227-CC was an interim model with TPE331-11U turboprops, and only five were built; the SA227-DC, the subject of this page, received the more powerful TPE331-12 and became the production model. Jane's All the World's Aircraft 1991-92 dates FAR 23 type approval to June 1990 for the version with TPE331-11 engines and to September 1990 for the Metro 23 with TPE331-12s. The FAA type certificate data sheet A18SW gives the exact day: the Model SA227-DC, in the commuter category, was approved on September 29, 1990. Its certification basis combines FAR 23 through Amendment 23-34 with Amendment 23-39, plus an equivalent safety finding in an FAA letter dated September 20, 1990, and it is approved for flight into known icing. The same data sheet allows an SA227-CC to be converted into an SA227-DC, and vice versa, to Fairchild drawings.

The FAA accepts three versions of the Garrett (AiResearch) TPE331-12 for the SA227-DC: the 12UA-701G, the 12UAR-701G and the 12UHR-701G. Jane's describes the TPE331-12UA-701GS as giving 745.5 kW (1,000 shp) dry and 820 kW (1,100 shp) with the continuous alcohol/water injection system, whose 60.5-litre tank sits in the nose (the Metro III lacks it). The FAA data sheet, for its part, lists 1,100 shp for a five-minute take-off and 1,000 shp maximum continuous. Each engine drives a McCauley four-blade metal propeller, constant-speed, reversible and fully feathering, with automatic synchrophasing and in-flight windmill start capability. The two integral wing tanks hold 2,452 litres of usable fuel.

The Metro 23 was the high-gross-weight member of the family. Jane's notes that the Metro III was cleared for take-off at 6,577 kg, with an optional 7,257 kg, whereas the Metro 23 reaches 7,484 kg at take-off. Its other weights, from the same source, are 7,530 kg ramp, 7,110 kg landing, 6,577 kg zero-fuel and 3,935 kg operating empty. The FAA limits the cabin to 19 passengers and permits single-pilot operation provided the instrument panel follows the approved arrangement. The passenger cabin is 7.75 m long with a volume of 13.88 m³; behind it is a pressurised hold for 385 kg and in the nose another for 363 kg, and the interior can be converted to all-cargo or mixed layouts with a movable bulkhead.

At its 7,484 kg maximum weight, Jane's credits the Metro 23 with a maximum cruising speed of 534 km/h at 3,353 m, a service ceiling of 7,666 m (3,505 m with one engine out), a sea-level rate of climb of 698 m/min, a take-off distance to 15 m of 1,414 m and a landing run of 843 m. Range with 19 passengers and baggage, with FAA IFR reserves, is over 1,450 km, and with 2,720 kg of payload over 967 km. It spans 17.37 m, is 18.09 m long and 5.08 m high.

According to the type's history, 110 SA227-DCs were built, 37 of which went to the US armed forces as C-26Bs. The FAA assigns the model serial numbers from DC-784 upwards and tells them apart by the final letter: C-26Bs, built to a specific Fairchild drawing, end in M, and all others in B. Jane's records that one plus nine C-26Bs were ordered in fiscal year 1990, with quick-change passenger, medevac or cargo interiors. The same yearbook announced that the Metro III would stay in production only until October 1991, leaving the Metro 23 as the line's model. On that basis Fairchild offered a Metro 23 EF with an under-fuselage baggage pod, the Expediter 23 freighter and the Merlin 23 business version, launched in November 1990 at Phoenix, Arizona.

Metro production ended in 1998, when regional jets were in vogue and turboprops had fallen out of favour with airlines; several unsold airframes remained at the factory. The last of them, Metro 23 c/n DC-904B, was not delivered until 2001, to National Jet Aviation Services, an air charter operator in Zelienople, Pennsylvania. Fairchild Aircraft transferred type certificate A18SW to M7 Aerospace of San Antonio, Texas, on April 29, 2003.

The SA227-DC flew with regional airlines — Australia's Regional Express had Metro 23s in its fleet — and on government missions: the Colombian National Police uses several Metro 23s for counternarcotics reconnaissance and the Peruvian Air Force operates one in a similar configuration. Its record also has dark pages. On May 7, 2005, SA227-DC VH-TFU, owned by Transair and operated as Aero-Tropics Flight 675 from Bamaga to Cairns via Lockhart River, Queensland, struck the South Pap ridge 11 km from that aerodrome during an approach in poor weather. All 15 people on board died, the worst airline crash in Australia since the 1960s; the Australian Transport Safety Bureau (ATSB) attributed it to controlled flight into terrain. Transair went into liquidation in late 2006. On February 24, 2020, an SA227-DC of Perimeter Aviation operating Bearskin Airlines Flight 344 left the runway while taxiing at Dryden, Ontario, and struck a snowbank; fragments of the left propeller penetrated the cabin and injured passengers. On December 10, 2021, another SA227-DC, Castle Aviation Flight 921, carrying medical supplies, crashed in Bedford, New Hampshire, on approach to Manchester; its sole occupant, the pilot, was killed.