Question: What is the engine type of the plane in service in AirTran JetConnect?

Context paragraphs:
Ferrari 312 P: The Ferrari 312 P was a Group 6 Prototype-Sports Car used for racing in 1969 and 1970.  The new 1971 version of the sports prototype came with a flat-12 engine, often referred to as a boxer engine.  Many publications added the letter B after the P of its name to indicate its engine type, but this variation was never officially sanctioned by Ferrari which simply called it the 1971 312P.

Nissan D engine: There were more than one engine type named Nissan D-series:

Parks P-2: The Parks P-2, powered by a 150 hp Axelson-Floco B engine was a biplane designed and built at the Parks Air College in the United States circa 1929.  A change in engine type to the Wright J-6 resulted in the Parks P-2A which was ultimately marketed as the Ryan Speedster after rights were bought by the Ryan company.

Regular Production Option: A Regular Production Option (RPO) is a General Motors standard coding for vehicle configuration options.  These codes are a combination of 3 alphanumeric characters and refer to a specific option or modification to the vehicle.  These codes signify how the vehicle is built during production and thus the specific configuration of a vehicle as it exits the factory up to and including the paint color can be described by specifying the base model and the complete list of RPO codes used during production.  Even a vehicle with no extra-cost options will have some RPOs, as information like the engine type and exterior paint color are always specified.

Jaguar AJ-V8 engine: The Jaguar AJ-8 is a compact DOHC V8 piston engine used in many Jaguar vehicles.  It was the fourth new engine type in the history of the company.  In 1997 it replaced both designs previously available on Jaguar cars: the straight-6 Jaguar AJ6 engine (or rather its AJ16 variant), and the Jaguar V12 engine.  It remained the only engine type available on Jaguar until 1999 with the launch of the S-Type, when the Jaguar AJ-V6 engine was added to the list.  The AJ-V8 is available in displacements ranging from 3.2 L to 5.0 L, and a supercharged version is also produced.  Ford Motor Company used this small V8 in other products as well, including the Lincoln LS the 2002-2005 Ford Thunderbird as well as in several Land Rovers and the Aston Martin V8 Vantage.

AirTran JetConnect: AirTran JetConnect was the brand for AirTran Airways former regional airline service, which flew regional jet aircraft from AirTran's hub in Atlanta.  Service was to short-haul markets where AirTran felt their Boeing 717 or Airbus A320 (with the latter type being operated by Ryan International for AirTran via contract) mainline jet aircraft were too large to economically operate.

Boeing 717: The Boeing 717 is a twin-engine, single-aisle jet airliner, developed for the 100-seat market.  The airliner was designed and originally marketed by McDonnell Douglas as the MD-95, a derivative of the DC-9 family.  Capable of seating up to 134 passengers, the 717 has a design range of 2,060 nautical miles (3,815 km).  It is powered by two Rolls-Royce BR715 turbofan engines mounted at the rear of the fuselage.

Overspeed (engine): Overspeed is a condition in which an engine is allowed or forced to turn beyond its design limit.  The consequences of running an engine too fast vary by engine type and model and depend upon several factors, chief amongst them the duration of the overspeed and by the speed attained.  With some engines even a momentary overspeed can result in greatly reduced engine life or even catastrophic failure.  The speed of an engine is ordinarily measured in revolutions per minute (RPM).

Ambrosini SAI.2: The Ambrosini SAI.2 was a light monoplane built in Italy in 1934.  Like the SAI.1, it was designed to participate in the "Avioraduno del Littorio" rally of 1935.  Compared with that aircraft, the SAI.2's wing area was only 1.4 m² (15 ft²) less, but the reduction in drag as a result of the monoplane configuration versus that of a biplane resulted in a top speed 20 km/h (12 mph) higher.  Both aircraft used the same engine type.

Toyota model codes: Every Toyota vehicle has a model code which describes the basic vehicle (e.g. Corolla), its generation and major options (engine type, gearbox type, body style, grade level).  The model codes fall into three periods, 1937 to late 1950s, late 1950s to late 1970s and late 1970s to present.  There was some overlap as new models were phased in using new codes while old models were phased out using the old codes.  The model code is not the same as the VIN.

Supporting paragraphs: AirTran JetConnect Boeing 717
Answer: twin-engine