Embraer’s study of an upgrade for its family of E-Jets should be completed by the end of 2012, with Rolls-Royce now among the three engine makers being considered by the Brazilian airframer.

The company previously said it was talking to General Electric, Pratt & Whitney and CFM International, but now names the candidates as CFM, P&W and Rolls-Royce. The CFM engine will be a Leap X variant available for service in 2018, while the P&W offering will be a member of the PW1000 geared turbofan version, ready in 2016. The possible Rolls candidate is currently not being disclosed.

Even without adding a contemplated longer version to the E-Jet range, the difference between the largest and smallest aircraft in the family will demand two different engines, Paulo Cesar de Souza e Silva, president of Embraer’s commercial aviation business, tells Aviation Week during the Singapore Airshow. The current E-170 and E-175 are fitted with General Electric’s CF34-8 engine, while the E-190 and E-195 have the more powerful CF34-10, along with a larger wing.

Embraer is studying a longer landing gear to make room for engines with larger fans and therefore lower specific fuel consumption, says Chief Technology Officer Mauro Kern. The Mitsubishi Aircraft MRJ, a close competitor to the E-Jet, will have PW1217G engines with fans of 1.42 meter (56 in.) in diameter. The fan of the CF34-10 is 1.35 meter in diameter.

De Souza stresses that the upgraded aircraft will have more than new engines, with possible changes to the wings among the more likely developments. But de Souza adds the company has yet to determine if that will mean a refined aerodynamic profile, a different platform, modifications to flaps and ailerons, or some combination of those changes.

New and heavier engines also may demand a beefier structure, and Embraer previously said it will consider updating the cockpit and installing a full fly-by-wire flight control system in an updated E-Jet.

The possible upgrade was announced in November after Embraer dropped consideration of a new and larger aircraft when Airbus and Boeing decided to re-engine their narrowbody programs, rather than opt for larger clean-sheet designs.

Embraer forecasts global demand for 4,125 aircraft in the 91- to 120-seat range in the coming 20 years, and 2,670 in the 61- to 90-seat range. It also expects airlines to buy 430 aircraft with 30-60 seats, but says it is not considering an update of its ERJ family.