Yakovlev, project leader for Russia's MS-21 next-generation narrowbody programme, will issue a call for tenders for the aircraft's systems in October, as critical decisions about the twinjet's basic design and configuration approach.

The MS-21, which is being developed under the United Aircraft (OAK) umbrella, is managed by Andrei Matveyev, who says that tenders for systems will open in October. However, the design effort is running a month behind schedule. It was due to have reached the "Gate 2" freeze of external dimensions and vital technical characteristics in August.

The aircraft's development schedule is operating to the Boeing-derived eight-gate system, with Gate 2 a critical point in the definition as it marks the point where the number and size of the family members are finalised, and specifications set for the major systems.

Matveyev will not reveal any preliminary MS-21 data, citing the need to keep a "high secrecy regime" due to the tough competition that exists between Yakovlev and its Western rivals Airbus and Boeing as they "all shape their next-generation narrowbody". Yakovlev has revealed only basic data for a planned three-model family seating 150, 180 and 210 passengers.

However, sources close to the programme indicate that as the definition freeze nears, fundamentally different configurations are still being examined, with the classic single-aisle cabin's six-abreast layout being weighed against a wider, 4.2m (13.8ft)-diameter fuselage option (against 4m) incorporating a twin-aisle, two-two-two seating arrangement.

A key element of the MS-21 is the engine, says OAK vice-president for MS-21 and NPK Irkut president Oleg Demchenko, who expects Rolls-Royce and Pratt & Whitney to go head-to-head in the soon-to-be-launched tender. R-R is likely to pitch its open rotor design against a version of P&W's PW1000G geared turbofan.

An R-R source told Flight International that the company is considering MS-21 participation, and that it can develop and certificate its engine before the MS-21 is due to be certificated in the first quarter of 2015.

Meanwhile, local engine manufacturers are offering two solutions. One, the SPM-21, is a joint offer from Russia's MMPP Salyut and Ukraine's ZMKB Ivchenko-Progress and Motor-Sich. The engine is based on technologies developed for the Antonov An-70's D-27 propfan.

Perm is proposing its PS-12 next-generation turbofan family of classic design, except for the highest 40,000lb-thrust (178kN) version that features a geared fan.

The MS-21 is OAK's most ambitious project, with airframe and systems development valued at an estimated at Rb150 billion ($6 billion). In July the Russian government and OAK's Yakovlev design bureau signed an agreement for Rb70 billion to be provided to fund MS-21 research and development under a state budget non-refundable allocation.

Source: Flight International